Health, with a Grain of Salt

Explaining the science and debunking the myths of nutrition, metabolism, and health.

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Big Changes to the Nutrition Facts Label

junk food aisle

Did you hear?? The biggest news in nutrition policy in two decades?? The new Nutrition Facts Label is here!! (I’ll wait while you compose yourself after all the cheering, celebrating, and champagne popping…)

Last week, Michelle Obama presented the new FDA food label at the Partnership for a Healthier America conference on behalf of the Let’s Move! program. The food label was first introduced in 1991, and other than the addition of trans fat in 2006, the label really hasn’t changed in the last 25 years. Needless to say, it was ready for a facelift. Here’s a side-by-side comparison of the old vs new labels.

NFL Side by SideWhat Changed? Why Should I care?

  • More emphasis on serving size and the number of servings in each package. Two thumbs up. The serving size also has to reflect what someone will actually eat. I have mixed feelings about this. On the one hand, I think this is good because most of us don’t drink half a bottle of a beverage, despite labels that often list “2 servings/bottle.” Now, the calories will more closely reflect what we actually consume. On the other hand, what is listed on a package does not necessarily correspond to how the USDA defines serving sizes of given food groups (most packaged foods will list larger serving sizes). In the 170 page document explaining the changes to the label regarding serving sizes, the FDA acknowledges that “portion sizes have changed since we first published serving size regulations in 1993.” What these changes mean is that 12 oz. and 20 oz. bottles of soda will both equal one serving size because people will drink the entire bottle, no matter the size. This seems like it may confuse some people with regard to how much of a food they should consume, but maybe I’m overthinking it.
  • Calories are listed in BIG, BOLD FONT. Because calories matter.
  • “Calories from fat” are no longer listed due to the large body of evidence demonstrating that total dietary fat intake does not a bad diet make.
  • The change everyone is talking about: added sugars. Before now, you weren’t able to tell how much sugar was added by the manufacturer vs how much sugar naturally occurred in the food (mostly from fruit and dairy). Now, you’ll know both grams and the percent daily value of added sugar (the Dietary Guidelines for Americans recommend that no more than 10% of total calories come from added sugar). As you may have guessed, food companies got all in a tizzy about this because they add way too much sugar and now they can’t hide it anymore. Bummer for them, yay for you.
  • Quantities and not just percentages of micronutrients will now be listed. This probably matters most to nutrition nerds like myself, but it also means that you can see the actual value of the micronutrients, much like with the macronutrients (fat, carbs, protein).

When Will My Food Be Covered in It?

  • Food manufacturers will have to use the new food labels by July 26, 2018.

Does Any of This Matter?

  • Not sure. Cynics argue that this only matters for the affluent and nutrition conscious groups, people whose diets don’t need as much attention, while not really changing anything for lower-income folks. And this new label probably won’t change anything for the millions of people who already ignore them. We don’t have evidence that points one way or the other, but I think this is a step in the right direction as it will likely lead to reformulation of some products (particularly those high in added sugars). Transparency is also important and the new label is easier to read and understand than the old one. Plain and simple.

Marion Nestle, PhD, Professor at NYU and nutrition and public health extraordinaire, said it best, so I’ll leave you with some food for thought from her:

“I see the new label as a political win for public health and Let’s Move!  But let’s keep this in perspective.  Healthful diets are based on foods, not food products.  We would all be healthier eating foods that do not come with Nutrition Facts panels, and saving most of those that do for once-in-a-while occasions.”

 

The Set Point, the Settling Point, and What You Can Do About It

scale-Hans Splinter, Flickr

In my last post I discussed the complexities of obesity and some of the metabolic and neurobiological effects that cause weight gain and maintenance of a higher body weight. I received a question from my longtime friend and follower, Hayley, about the defense of weight. She asked, “Once an obese person loses weight does their body ever reset again? Or will their body try to reach its highest weight for the rest of their lives?”

These are great questions and I’ll answer them out of order. There seems to be no definitive answer for the second question so I’d like to go over a couple of the predominant theories in the field of body weight regulation to offer some insight on that question.

Set Point Theory
The set point theory focuses on biological control of weight and fat mass and posits that there is a control system (genes and hormones from the gut, brain, and adipose tissue) dictating how much fat someone should carry, which varies from person to person. I’m going to focus on fat (adipose tissue) mass because this is much more malleable and what we’re generally talking about when we talk about weight loss. Fat mass regulation is controlled by both sides of the energy balance equation (intake and expenditure) and the set point theory suggests that changing one side of the equation will lead to corresponding changes in the other. For example, if you reduce intake, the body will reduce expenditure to try to maintain fat mass. That is, the body will “defend” its highest sustained weight, ultimately thwarting your best efforts to lose weight and keep it off. However, it’s important to emphasize that this is a theory that has not been proven and isn’t accepted by all obesity scientists and physiologists. Indeed, the set point theory may be too simplistic because it does not explain why the world’s set points have gone up over the past 50 or so years and is contradicted by data that demonstrates that starvation and subsequent refeeding can result in even higher body and fat mass than the initial weight (that is, the body overcompensates after extreme weight loss).

Settling Point Theory
That brings me to the idea of the settling point theory, which focuses almost entirely on the environment and human behavior. This is the idea that body fat levels will “settle” into a given range in response to the habits that a person practices. So, if food is highly available and you don’t have to work very hard to get it (i.e. America), your body fat may “settle” at a higher point. Conversely, if you are put into an environment of low food availability and high physical demand, your fat stores will settle at a lower point. There are data to back up this idea: the current food environment supports increased energy intake due to the abundance of extremely tasty, calorically rich food that is served in large portions coupled with the fact that we have to do very little physical work to live (thank you cars and washing machines). However, this theory doesn’t take into account any biological control of weight, despite the fact that numerous studies have shown that biological regulation of fat mass exists. For example, in the Minnesota Experiment that I previously mentioned, severe caloric restriction resulted in marked weight loss that plateaued at a certain point (support of the settling point theory). However, when subjects were allowed to eat whatever they wanted, they didn’t simply resume their old habits and slowly regain the weight. Instead, they regained weight and fat mass rapidly, indicating that they were over-eating in an attempt to restore fat and lean mass. They did, in fact, restore mass and then some. This suggests that there are active controls within the body to increase fat mass (i.e. evidence to support the set point theory). Furthermore, there are data that support the notion of changes in energy expenditure during times of starvation and overfeeding, indicating that the body is attempting to adapt to changes in intake (adaptive thermogenesis).

 

While both the set point and settling point theory have their shortcomings, it may be most reasonable to consider them together and recognize that biological control of intake and expenditure exists, but these can be overrun or attenuated by an obesigenic (obesity causing) environment. So, to answer Hayley’s second question: I haven’t seen data that shows, specifically, that people will always regain weight back to their exact highest weight and I don’t think everyone will. Further, as with everything with humans, there is likely a large amount of inter-individual variability and some will struggle with maintaining a healthy weight more than others. So, while I could find no clearcut answer, hopefully the two theories I presented along with the physiology I described in my previous post will give you some ideas of how this all works.

 

Now on to the first question: I have found some evidence/hypotheses to suggest that the set point can be reset. Here are a couple of tips that I have found:

  1. Exercise
    Professor Jim Hill at the University of Colorado suggests that our physiology works best at high levels of physical activity. Physical activity is likely to improve the body’s ability to assess its need for nutrients (and eat accordingly) as well as partition dietary fat to be burned instead of stored. So if you’ve lost weight, you’ll likely need to do a fair amount of exercise to keep that weight off. The good news is that every other system in your body (other than those regulating your fat mass) will thank you. The Physical Activity Guidelines for Americans recommend that 60-90 minutes of aerobic activity/day may be necessary to avoid weight regain, but remember: any amount is better than none.
  1. 10% rule
    One hypothesis for effectively losing weight and maintaining it is to use the 10% rule. The idea is that when you lose more than 10% of your weight, your body starts to resist by reducing its energy expenditure and increasing hunger cues in order to “defend the set point.” However, losing only 10% or less at a time may not trigger these responses and, thus, could lead to sustainable weight loss. One approach, as outlined by the online weight loss course at the Beth Israel Deaconess Medical Center at Harvard. After 6 months of maintaining that new weight, you are advised to lose 10% of your new weight and so on until the goal weight is reached (which is when you’ll really need to focus on the goal of 60-90 minutes of activity/day). I like this approach because it allows you to set realistic and attainable goals. For example, if your starting weight is 200 lbs, losing 20 pounds (and then 18 and so on) is easier to stomach than a goal of losing 50 all at once. And while I like the sound of it, I have yet to find any clinical trial that has tested this hypothesis. I’ve seen this 10%-weight-loss-6-month-maintenance-phase recommendation all over the internet, though there are never any accompanying citations (if anyone has seen these data, please send them my way). I’m wondering what the 6-month weight maintenance timeframe is based on. Perhaps something as short as 6 weeks or a few months would be equally beneficial. Overall, though, it’s best to think of weight loss as a journey instead of just a destination (sort of like life) and work through it at a slow, reasonable pace, learning new habits and lifestyle changes that are sustainable along the way.

 

Hopefully I’ll be able to find some kind of hard evidence on this “10% step down” approach. If I do, I will update this post with that information. As always, please don’t hesitate to offer insights and ask questions!

 

Obesity is Not a Disease of Sloth and Gluttony*

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The most recent data from the CDC indicates that approximately 35% of American adults have obesity (1). In order to reduce prevalence of this disease (yes, disease), a popular notion is that people with obesity just need to “eat less and move more.” Indeed, many public health programs use this concept as their primary approach for combating obesity. While eating less and moving more may help prevent obesity or result in successful, sustained weight loss in individuals who are overweight (but not yet obese), ongoing research indicates that these simple lifestyle changes will do very little in the face of prolonged obesity (2).

If you look at any weight loss study, you will most assuredly find the same results, regardless of study design. The first six months are generally characterized by substantial weight loss, followed by sustained weight regain, resulting in a final weight that is negligibly lower and potentially higher than the starting weight . Only about 20% of people who lose weight maintain that weight loss over the following year (3). This “checkmark effect” or weight loss recidivism that has been reported nearly ubiquitously across diet and exercise-based weight loss trials (4) indicates that lifestyle interventions, as they are currently designed and implemented, are generally not successful modalities for treating obesity.

Based on a rudimentary understanding of metabolism, the calories in/out approach should work for weight loss and weight loss maintenance. So why do so many people regain the weight? Is it an issue of willpower? In short, the answer is no.

The answer lies in the complex network linking the environment, genetic predisposition to obesity, as well as metabolic and physiological changes. A large body of literature indicates that the brain’s reward systems are significantly dysregulated in individuals with obesity (5). In an environment that supports ease of access to highly palatable foods, the pleasurable effects of consuming said foods can override homeostatic control of intake. While some people are able to regulate intake despite the high palatability of these foods, a number of genetic mutations in the brain’s reward systems may result in overeating and obesity in many people. Furthermore, the hypersensitive reward systems that often lead to obesity can become insensitive once a state of obesity is attained. In effect, this leads to overeating to receive the same reward from the same foods. These dysregulated reward systems are coupled with preadipocyte (young fat cell) expansion into mature adipocytes, allowing for increased fat storage. While this isn’t the entire story, this should shed some light on the complex interactions of dysregulated internal systems that foster the metabolic abnormalities that result in obesity. Importantly though, these impairments are typically only demonstrated once obesity has been introduced and sustained (4) and individuals who are overweight (but not obese) will likely not encounter many of these aberrations.

As for weight loss, when caloric restriction is initiated, the body triggers a number of systems to prevent starvation. From an evolutionary perspective, this makes sense as food sources were often unpredictable and the body adapted to conserve energy – the “feast and famine” principle. However, for most of us living in industrialized nations, famine is rare and feast is common, limiting the need for this once very necessary adaptation (however, the body has not evolved to recognize the abundance of calories in our modern food supply). When we try to induce weight loss via caloric restriction, the body will reduce its resting metabolic rate to counter these advances (6). This supports the “set point theory” – the idea that the body will defend its highest-sustained weight. In fact, as weight loss increases, the drive to restore the highest bodyweight only increases (7).

All of these biological adaptations that introduce, sustain, and defend obesity explain why weight loss and its maintenance is so exhaustingly difficult for so many people. In a commentary published in 2015 in Lancet: Diabetes and Endocrinology, Ochner and colleagues suggest that most individuals who have had obesity but lost weight simply have “obesity in remission and are biologically very different from individuals of the same age, sex, and body weight who never had obesity.” Hypothetically, imagine you are comparing two people: they weigh the same, but person A had obesity and has lost weight whereas person B has never lost weight. Person A will have to burn up to 300 more calories (or consume 300 fewer calories) than person B to maintain that weight (2). This underscores the idea that weight regain is not simply an issue of willpower and weakness.

What we need more of are studies evaluating multiple approaches to weight loss (perhaps diet and exercise studies with more innovative approaches to maintain weight loss; surgeries, medications, likely in combination with lifestyle changes). What we need less of is bias from people without obesity, the media, and even healthcare providers. Indeed, “the mere recommendation to avoid calorically dense foods might be no more effective for the typical patient seeking weight reduction than would be a recommendation to avoid sharp objects for someone bleeding profusely” (2). We also need better obesity prevention approaches because, clearly, it’s biologically more feasible to prevent weight gain than to lose weight and keep it off.

 

References

  1. Ogden CL, Carroll MD, Kit BK, Flegal KM. Prevalence of childhood and adults obesity in the United States, 2011-2012. JAMA. 2014;311(8):806-814. doi:10.1001/jama.2014.732.
  2. Ochner CN, Tsai AG, Kushner RF, Wadden TA. Treating obesity seriously: when recommendations for lifestyle change confront biological adaptations. Lancet Diabetes Endocrinol. 2015:
  3. Wing RR, Phelan S. Long-term weight loss maintenance. Am J Clin Nutr (2005) 82:222S-225S.
  4. Ochner CN, Barrios DM, Lee CD, Pi-Sunyer FX. Biological mechanisms that promote weight regain following weight loss in obese humans. Physiol Behav. 2013:120:106-13. doi: 10.1016/j.physbeh.2013.07.009.
  5. Kenny JP. Reward mechanisms in obesity: new insights and future directions. Neuron. 2011:69(4):664-79. doi:10.1016/j.neuron.2011.02.016
  6. Grattan BJ, Connolly-Schoonen J. Addressing Weight Loss Recidivism: A Clinical Focus on Metabolic Rate and the Psychological Aspects of Obesity. ISNR Obesity. 2012. doi:10.5402/2012/567530
  7. Rosenbaum M, Leibel RL. Adaptive thermogenesis in humans. Int J Obes. 2010:34:S47-55. doi:10.1038/ijo.2010.184

 

*Originally published in another form on the ASN Blog.

Photo by Skitter Photo on stocksnap.io

The Good, the Bad, and the Meh of the 2015-2020 Dietary Guidelines for Americans

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As you may have heard, the new 2015-2020 Dietary Guidelines for Americans (DGA) were released last week. The DGA were first created in 1980 and are updated every 5 years, based on new science. (If you think the Food Pyramid still exists, get with the program and check out MyPlate.)

myplate_yellow_livetype copyThere was potential for some great things in the new DGA. Some of that happened, whereas other facets are overwhelmingly vague and lack clear instruction or guidance for consumers. Here’s my take on the wins and losses regarding what changed (and didn’t).

The Good
Focus on Dietary Patterns, Less on Individual Nutrients –This is seemingly the focus of the whole 2015-2020 DGA, but it has gotten lost in the media coverage and because so much of the report is actually contradictory in nature and focuses on aspects of diet other than patterns (more on that in a minute). The meal patterns they recommend are a healthy American, vegetarian, or Mediterranean diet. All of these patterns have ample evidence to support them and the DGA point out that you don’t have to pick just one. You can switch them up based on what you feel like eating. They characterize a healthy eating pattern by lots of vegetables, whole fruits, grains (mostly whole grains), low-fat or fat-free dairy, a variety of types of protein, and healthy oils. I agree with all these recommendations, and I commend the DGA for emphasizing dietary patterns. However, they left some important things out and I’m pretty sure it wasn’t by accident.

The Bad
Meat – There is brief mention of men and boys reducing their intake of red meat, poultry, and eggs and increasing their intake of other protein sources including beans, nuts, seeds, and seafood. But 1) nobody actually needs meat, though it can be included in moderation. Yes, men and boys eat more meat than women, but based on the advisory committee’s report, just make the recommendation for everyone to eat less meat; and 2) there is no mention of processed meats, which are more of an issue than meat in general.

Portion Sizes – This is one of the biggest issues in the American diet. We like to point the finger at so many facets of our diet, but the truth of the matter is that we simply eat too much. People need to learn what a portion size of a given food looks like. The DGA would be the perfect resource for that, but they don’t go into it (not that I could find, at least).

Wordplay – This is by far the worst part of the DGA, as it always has been. Recommendations are vague and indirect. Though slight and subversive, when you should eat more of something, the rec’s mention “foods.” When you should eat less of something, the report mentions “nutrients” (i.e. salt, saturated fat, sugar; see below: The Meh). While the general focus is on overall patterns, this back and forth between foods and nutrients is confusing for consumers. Should we be following a pattern or do we need to be tracking our nutrient intake? People want to know how to improve their health, so be direct and tell them how: eat fewer processed foods, less meat, fewer sodas/sweetened beverages/sweetened yogurt/cake/cookies…sweet stuff. But why aren’t we told that? Because of politics. You don’t buy nutrients. You buy foods. So telling people to eat less of certain nutrients instead of certain foods is a creative way to appease the food industry. That’s because there are powerful lobbyists for the food industry, namely meat, soda, and processed food companies, who strongly influence what is (read: isn’t) included in the DGA. As per usual, these industries get a win from the DGA report, whereas the consumers, the people who are supposed to benefit from these guidelines, do not.

The Meh
Physical activity – The 2015-2020 DGA now have recommendations on physical activity…a bit suspect since physical activity is not diet. However, I’m not that bent out of shape about this because perhaps having both sets of recommendations in the same place could lead to people actually reading them. But we do already have a document for this exact purpose, and it’s called the Physical Activity Guidelines for Americans.

The Three S’s – The recommendations for salt (2,300 mg/day) and saturated fat (no more than 10% of total calories) remain the same, while a recommendation for added sugar (no more than 10% of total calories) was added.

Since the other two didn’t change, let’s focus on the sugar recommendation. While this does disagree with the whole “focus on patterns” thing because sugar is a nutrient, this recommendation is likely beneficial as we do need to curb our enthusiasm for added sugar in this counntry. I absolutely don’t support eating excess added sugar because it provides no health benefit. However, I’m also slow to vilify individual foods/nutrients, which is what has been happening with sugar. Americans love to let out a warcry against single nutrients that seemingly need to be burned at the stake (we’ve done it with fat, carbs, and now sugar). These efforts to demonize and blame all our health-related woes on a single nutrient have done exactly nothing to improve population health or reduce weight, long term. So my issue is not really with the DGA, but with the media coverage of sugar. It has been branded as poison and its effects on the brain equated with cocaine. Fear mongering never gets us anywhere with nutrition and sugar is no exception. Work on limiting your intake of added sugars, but there’s no need to be scared of it.

Sustainability? – The DGA are supposed to be based on information from the Dietary Guidelines Advisory Committee, a who’s who of nutrition and public health experts who write up a report with recommendations based on nutrition research. One of their recommendations was to include sustainability goals in the 2015-2020 DGA because, as they argued, what people eat probably shouldn’t desecrate the planet. What that means, in short, is that we should eat less meat. So, unsurprisingly, the meat industry FREAKED OUT and sustainability didn’t make into the 2015-2020 DGA. I would like to see some recommendations on sustainability as it relates to dietary practices so that people start paying more attention to it. However, my friend and colleague Michelle Cardel makes the very good point that nutrition scientists are not trained in sustainable agricultural practices. Perhaps a subsection based on reports from agricultural scientists and experts in sustainability would fill this need.

So, there it is. The good, the bad, and the meh of the 2015-2020 DGA: a document that hasn’t changed much over the past 35 years, but remains lengthy, vague, and full of wordplay that will satisfy industry and likely confuse consumers (that is, those who actually read it).

Image from flickr.com by Joshua McKenty

Becoming a More Thoughtful Consumer

Boil

The new year is a great time to reflect on the past year, considering what has worked and what hasn’t and to plan ahead for what you want out of the future. 2016 will be a big year for me with a likely job change and potentially moving to a new city. With all of that commotion and change, I’ve decided that the theme of the year is simplify. This is really a three-pronged approach, as I would like to simplify my finances (read: spend less), reduce my impact on the environment, and improve my health. As this is a health blog, I won’t be going into my approach for improving my financial situation, but I’m planning on doing a Spending Diet, which you can read about more on “And Then We Saved,” which has lots of great tips!

The beauty of this approach is that these three goals often go hand-in-hand. That is, when you choose to do something to improve your health, you are often going to reduce your impact on the environment and spend less money. Example: riding your bike for transportation.

Many people have a weight loss goal as their New Year’s Resolution, which can be good, but it can often be shortsighted and easy to throw in the towel. I prefer to consider lifestyle approaches that bring about other types of change that you can be proud of and may result in weight loss as a byproduct.

The two main approaches I’ll be using to address my three goals are 1) mindfulness and 2) reducing food waste.

Eating Mindfully

The whole idea of mindfulness is rooted in being intentional with your thoughts and actions. Instead of moving through life on autopilot, take a moment to ask yourself why you’re doing what you’re doing and if it aligns with who you are/want to be. In short, it is about being present. A couple years ago, I embarked on a self-inflicted nutrition experiment wherein I tried a different popular diet each month and blogged about the experience. On one such month, I practiced eating mindfully and loved it. I’ve lost many of those habits, so I’m going to work on bringing them back. Here are some of my favorite tips for eating mindfully.

  • Focus on Food Production. One of the best ways to be environmentally conscious and potentially benefit your health is to think about where your food comes from. The best thing you can do is buy locally grown food, perhaps organic, in an effort to support small farms and your community economy, as well as minimize the environmental strain of your food consumption. Depending on where you live, this may mean that food is more expensive than buying from the supermarket, but if you know where it’s coming from and if you’re spending a little bit more on it, you’re less likely to waste it. Step up: grow your own food, even if it just means having an herb garden or container garden. You’re bound to appreciate that food more and waste less.
  • Slooooow it Down. Most people eat too fast. It’s usually because we overbook our lives with events and eating becomes something that we rush through. Instead, take your time to eat because it’s the most important thing that you do everyday. Drink a glass of water before each meal in order to tell your gastrointestinal system that food is on its way, which will allow it to start producing the enzymes for digestion. It takes about 20 minutes after you start eating for your brain to send out satiety cues. Most people eat a meal in less than 20 minutes, so they don’t realize how full they are until after they’ve finished eating. Chew each bite to completion before taking the next. Set your utensil down between bites. This will give your body and brain time to tell you when it feels full and to stop eating, which may result in eating fewer calories. But by and large, it will teach you how to truly enjoy and savor food.
  • Distraction Free Diet. Oh boy, this one is hard. The idea here is to eat your food without being distracted by your phone, your computer, or your TV. These items take us out of the present moment and often prevent us from enjoying our food. Have you ever eaten a meal while watching Netflix and then thought back a few minutes later and realized that you don’t even remember how your food tasted? This is common and often leads to overeating. Instead, sit down at the table by yourself or with friends and family (eating is a social experience and often keeps us present in the moment, so don’t get rid of that) and actually pay attention to your food. Notice flavors, textures, and colors. Thank yourself or whoever prepared the food for you, whether audibly or just as a thought, and enjoy that big bad beautiful meal.

Waste Not
In America, we waste roughly 1/3 of the food that we produce. A lot of that is wasted commercially, but much of it is in the home. Here are some tips for doing your part to waste less, which will also help you eat healthier and save money.

  • Share. Nearly all portions served at restaurants are at least twice as large as they should be. If you eat out, share your entree with a friend. If that doesn’t work, save half of it for your lunch or dinner the next day. Thus, you will be reducing waste and saving money. Two birds, meet one stone.
  • Plan. Before you go to the grocery store every week, plan what you want to buy. Look in your refrigerator and pantry and see what you have. Plan your meals based on that so that you buy and throw out less food.
    • For example (actual example of what often happens to me), let’s say you have some cilantro, two green onions, half a bell pepper, some tofu or chicken, and a can of black beans. You have the makings for both Asian and Mexican type dishes. Round those ingredients out with some tortillas, rice/noodles, more veggies, spices (if needed), and sauce (or make your own) to make tacos one night and a veggie and tofu stir fry the next.
    • Next, make a list of a few meals (consider what your week looks like and how many meals you will realistically cook at home) and their corresponding ingredients. Plan your shopping list based on the store layout so you don’t forget anything. Buy most things in bulk (particularly grains, produce, nuts/seeds, etc.) so you can buy only what you need, which will help to reduce waste.
    • Buy produce that is in season. This will save you money because in-season produce is cheaper than out-of-season and tastes way better when it’s fresh. It’s also better for the environment because strawberries bought in January had to travel from very far away, which costs a lot in fossil fuels. Save those summertime dishes or snacks you love for the summer and learn how to cook winter veggies in the winter. You know, the way you’re supposed to.
  • Prepare. This next step takes a little bit of time, but your week will be oh-so-much smoother if you do it. Meal prep. If this intimidates you, start small by just chopping up veggies and fruits so that they are ready for snacks or for cooking. Consider what the hardest part of cooking is for you when you’re tired and don’t want to do it and try to make that step easier by doing it ahead of time. Before I started doing meal prep, it seemed pretty impossible and daunting. Here are some of my tips to take away some of the question marks.
    • Veggies. These should be the foundation of your diet and can take some time. I either stir fry or roast A LOT of veggies for the week. Then, I can mix them with pasta/rice, some kind of protein or put them over greens to make a salad.
    • Protein. I usually eat tofu, beans, or chicken for my protein for the week. I typically do a combination of two so that I have options to combine with my veggies.
    • Grains. I’ll either make rice, quinoa, or pasta. It just depends on what other foods I’m cooking for the week.
    • Quiche/Casserole. Mix something together quickly that may have to bake for awhile. This means that there’s a lot of hands off time so that you can do other stuff while it is baking. I usually do quiche filled with veggies and cheese because that’s what I like best, but you could do a number of other casseroles or lasagna.
    • Soup. This is where the crockpot comes into play. Just search for recipes online if you don’t have any ideas. Throw it all in the crockpot and let it cook for a few hours.
    • How it works: I usually chop up the veggies and start roasting them first (~30-40 min, depending on what you’re roasting). If I’m cooking chicken, I’ll usually roast that at the same time. I’ll also chop up everything for a soup and throw that in the crockpot. Then, I’ll put quinoa/rice in the rice cooker to start cooking or I’ll boil pasta. While the veggies are roasting, I’ll put together the casserole/quiche and then put that in once the veggies are done. While the quiche is cooking, I put everything away in tupperware and clean up the kitchen. From start to cleanup, this usually takes me 1.5 hours.
    • Add-ons: In addition to what I buy for prep, I usually have greens and usually some cans of beans for salads, fruit for snacks, and avocados and salsa for garnishes. I just mix and match what I’ve made in order to make hearty meals, so you have to do some planning so that themes overlap…unless you want to eat Italian with Caribbean. You do you. Recognize that you may not get this right the first time. Be patient and try new things.
  • The beauty of doing all of this is that you will definitely waste less food since most of it is already cooked. You’ll also have the time to do other things you want to do instead of cooking (i.e. working out, spending time with your family, doing your favorite hobby). It will also help you to stick with your nutrition goals and eat less junk since it’s already ready for you to enjoy.

What are your goals for 2016? Do you have any questions or comments regarding living (and eating) more simply? And for those of you who already do meal prep, how does your process compare to mine? I’d love to know!

 

Image by Pawel Kadysz on stocksnap.io

Don’t Trust the Headline: No, Vegetarian Diets are Not Bad for the Environment

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This week in my new favorite segment, “Don’t Trust the Headline,” many, many articles have been reporting that a new study just concluded that “lettuce is worse than bacon for the environment.” As a health conscientious individual, I’m often thinking about how my lifestyle impacts my health as well as this beautiful planet that houses me. Like many people, I limit my consumption of meat for both my wellbeing and that of The Mother, so I was a little perplexed when I saw headlines like the aforementioned as well as this one from Science Daily:

 

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So, like any good scientist, I decided to find said paper and read it for myself. Before reading, I considered that this paper may have been funded by meat lobbying groups, but it wasn’t. It was funded by the Colcom Foundation and a grant from the Steinbrenner Institute for Environmental Research at Carnegie Mellon. Nothing suspicious there.

The paper was published in Environment, Systems & Decisions and the more I read, the less I liked the media.  The aim of this study was to determine how changing our diets can impact the environment as there has been a call for the dietary guidelines to mesh with environmental sustainability goals. Further, given the obesity epidemic, there is also a recommendation for people to eat fewer calories (amongst other goals). The authors of this study evaluated three possible scenarios:

  1. Reduce caloric intake in order to facilitate weight loss.
  2. Adhere to the Dietary Guidelines for Americans (DGA) without reducing caloric intake.
  3. Adhere to the DGA and reduce caloric intake.

This was a meta-analysis that used various databases to determine how many calories we consume in America and how much it costs in terms of blue water, greenhouse gas emissions, and energy usage in order to produce over 400 types of food. What they reported was a bit surprising: “shifting from the current US diet to dietary Scenario 1 decreases energy use, blue water footprint, and GHG emissions by around 9 %, while shifting to dietary Scenario 2 increases energy use by 43 %, blue water footprint by 16 %, and GHG emissions by 11 %.” Shifting to Scenario 3 “increases energy use by 38 %, blue water footprint by 10 %, and GHG emissions by 6 %.”  *cue jaw drop*

That’s about the extent of which the media covered this topic (that is, they read the abstract), but things just didn’t really seem to add up. Here are some things that I took away from this paper:

  • Calorie to calorie comparisons. This analysis compared production costs of one calorie of a given food to another. This is an issue because when we replace meat with vegetables, we typically aren’t aiming to eat the same number of calories.  Four strips of bacon provides 175 calories, whereas you’d need to eat about 20 cups of shredded lettuce to get the same caloric load. Good luck. A better comparison would be pound-to-pound.
  • Food Waste. This study did something that most don’t and considered calorie consumption, not just intake. Calorie consumption includes intake as well as food waste (both personal and what’s lost at the commercial level).  Current caloric intake was estimated at 2,390 kcals/day/adult American. However, calorie consumption was estimated at a whopping 3,620 kcals/day/adult based on the conservative estimate that 34% of food is wasted at the consumer and commercial/retail levels (estimates range from 34-42%). What this tells me above and beyond anything else is that the greatest food production related effect we can have on our environment, not to mention our wallets, is wasting less food.
  • Fish/seafood and dairy consumption. It’s well described that raising meat has a huge impact on the environment. Pork and beef produce lots of greenhouse gases and require a huge amount of energy and water to grow. The DGA recommends eating less meat than Americans currently do, but the guidelines have recommendations for high dairy and seafood/fish consumption. I disagree with the dairy guideline because dairy isn’t necessary to have a healthy diet, but as this study shows, if we are to meet the dairy guidelines, we have to be eating a lot more dairy (~204 more kcal/day). That means that we need more dairy farms, which are not good for the environment. And then there’s fish/seafood. From a health standpoint, I highly recommend eating fish, but based on the results from this study and others,  it isn’t a very sustainable option. Farmed fish requires a lot of energy, while fishing wild fish/seafood is the second highest driving force in greenhouse gas emissions. Neither option is good so unless we come up with something better, the guidelines for fish intake likely need to be altered if we want our recommendations for human health to sync with those for planetary health.
  • Vegetarian diet wasn’t tested. Many headlines claimed that vegetarian diets are worse for the environment than omnivorous diets, but vegetarian diets weren’t actually tested. Perhaps many writers deduced this from the comparison of lettuce to bacon, but most vegetarians aren’t eating lettuce as their main source of calories.  Grains, beans, and soy are the primary caloric sources for many vegetarians. This analysis showed that production of these foods have some of the smallest influence on the environment so changing consumption patterns doesn’t do much to the environmental impact estimates made in this study. Finally, based on results from prior studies, the researchers concluded that “adopting a vegetarian diet or even reducing meat consumption by 50% is more effective in reducing energy use, the blue water footprint, and GHG emissions through the food supply system than adopting a healthier diet based on regional dietary guidelines.” Thanks for not reading the paper, media.

This paper is by no means the final word in deciding how we should eat in order to strike the best balance between human and environmental health. The data they used was limited in that most of it came from other countries because of the lack of analyses done here in the US. Thus, we need more research using more precise methods of data collection that are directly applicable to the US. However, this paper provides the justification to do just that. What I took from this paper, though, is that we waste too much food in the US, we depend too heavily on food from land that can’t support the agriculture (think: drought-stricken California), and the environmental consequence of transporting food all across the country (or world) is enormous. But what I did not take away from it is that we should eat more meat.

Image by Monstruo Estudio.

The Code for Obesity – Written in the Sperm

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Finally some focus on the importance of paternal health! There’s LOTS of research on the effect of a mother’s health (and even grandmother’s health) on her child, particularly with regard to obesity. In fact, when using the search terms “maternal health, obesity, children” on PubMed, nearly 2k publications popped up. Using the same search terms, but swapping out “maternal” for “paternal,” only 160 studies fit the bill.

However, new research published last week in Cell Metabolism adds to the relatively small body of literature focusing on paternal health. You may have seen this in the headlines as the Washington Post declared that obesity “makes sperm weird” (insert image of writers in the WP newsroom giggling like schoolchildren).

I don’t want to give these sperm a complex, so let’s not call them “weird.” They’re just different. But they are different in potentially very important ways that have to do with epigenetics.

As a brief background, epigenetics is the study of how a cell regulates what genes are turned on or off based on external or environmental factors. That is, a person’s gene’s don’t change, but whether those genes get expressed is often a matter of environmental influences (i.e. diet, physical activity, pollution, etc.). Additionally, there’s a plethora of research about how epigenetic codes from a parent can influence a child’s gene expression. One important epigenetic signal is DNA methylation. In general, when genes are methylated, they are locked in the “off” position, and this is important for a number of processes including embryonic development and cell differentiation.

The study in question by Donkin, et al. evaluated the epigenetic signatures in sperm samples from lean men (n=13) and men with obesity and poor glucose control (n=10), as well as from men with Type III Obesity (BMI ≥40.0 kg/m²; n=6) before and after undergoing gastric bypass surgery. Previous work indicates that children of obese fathers have an increased risk of developing metabolic diseases. The authors point out that this phenomenon is not simply due to behavioral traits that a child learns from a parent or socioeconomic status, as this effect has been observed in rodent studies as well as epidemiological studies where SES can be controlled for.  What the researchers found in this study is that DNA methylation profiles in sperm from men with obesity are distinctly different from lean men. Importantly, many of these differences in methylation were related to genes that govern processes like appetite regulation as well as those linked to obesity and fat mass. Furthermore, a week after undergoing gastric bypass, methylation of over 1,500 genes were changed in sperm, whereas almost 4,000 had changed 1 year post surgery and after weight loss of ~10 kg/m².

Ultimately what this study shows us is that paternal weight can influence what is passed into the germline, independent of his genes. In the words of Romain Barrès, one of the study’s coauthors, “Obese men have information that can be transferred to children that could potentially affect their eating behavior. And this information can be changed if obese men lose weight. Our study doesn’t show what is transmitted to children, but it is likely that something is transmitted and it will change brain development and behavior.” That’s to say that future fathers (not just mothers) likely need to be paying attention to their weight and metabolic health.  I’m hoping more research in this field comes out soon, particularly on how these messages are actually transmitted to offspring and the effect they have on children’s weight and overall metabolic health.

 

 

Image by Oliver Dodd on flickr.

What’s the Deal With Red and Processed Meats?*

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[Before we get into this, I want to say that I’m not a huge supporter of red or processed meat consumption, contrary to what you might think after reading this post. There are plenty of health, ethical, moral, and environmental reasons to either not eat or limit intake of red and processed meats, which I will not be getting into here.  However, my goal is to lay out the facts so that people can make their own decisions based on evidence and not in response to media-driven fearmongering.]

If you’ve spent any time on the internet in the last couple of months, you’ve likely heard about the recent statement on red and processed meat from the World Health Organization (WHO).  The statement was produced by a Working Group of 22 scientists who gathered together at the International Agency for Research on Cancer (IARC), with the goal of considering all data from over 800 epidemiological studies on red and processed meat in order to determine their potential carcinogenicity. The group defines red meat as “mammalian muscle meat – such as beef, veal, pork, lamb, mutton, horse, or goat” and processed meat as “meat that has been transformed through salting, curing, fermentation, smoking, or other processes to enhance flavour or improve preservation” (1).  Based on the available data, the Working Group concluded that “that there is sufficient evidence in human beings for the carcinogenicity of the consumption of processed meat.” And then the internet exploded.

The IARC is responsible for classifying chemical compounds based on the strength of evidence that said chemical may be carcinogenic. In this statement, they classified processed meat as a Group 1 carcinogen and red meat as a Group 2B carcinogen.  These classifications are used to describe the strength of evidence that these compounds may be carcinogens; thus, Group 1 is used to distinguish “established carcinogens” [e.g. acetaldehyde (a metabolite of alcohol), oral contraceptives, formaldehyde, and sawdust], whereas Group 2B includes compounds that are considered “possible carcinogens” [e.g. benzofuran (a compound in coal tar), butylated hydroxyanisole (an additive found in foods, cosmetics, rubber, etc.)].

And while these classifications are important, they are easily misconstrued, as was the case in this statement by the IARC. These classifications simply tell us that a compound could be hazardous to human health. What they don’t tell us is degree of risk.  That’s important because lots of things can be hazardous without posing a significant risk.  For example, UV radiation is a hazard to health, but it is only a risk if one is exposed to excessive amounts of UV radiation.  That is, risk is the product of hazard multiplied by exposure. Reduce your exposure, reduce your risk. That’s where most people got confused with this IARC statement.

The media jumped on the statement and let out a warcry against red and processed meats.  But what most of them failed to mention is the all-important question: how much red and processed meat need be consumed to increase risk for developing cancer? One meta-analysis found that risk of colorectal cancer increased with increasing intake of red and processed meats up to 140 g/day (~5 oz/day) (2).  Further, risk of developing colon cancer in response to consuming red/processed meat increases by ~25% for every additional 100g consumed/day.  Thus, this study was showing an increased risk in consumers who eat a lot of red and processed meats. Importantly, these effects were strongest in European (29% elevated risk/100 g/day increase in intake) compared to North American (11% elevated risk/100 g/day increase in intake) and especially to Asia-Pacific studies that observed a non-significantly reduced risk (6% reduced risk/100 g/day increase in intake).  These results indicate that not all populations are equally affected, which is likely due to differences in genetics and/or lifestyle.  And what about people who don’t even eat red/processed meat everyday?  Are they at risk just by eating these foods once in awhile? A meta-analysis by Norat, et al. (3) estimated that reducing red and processed meat consumption to 70 g/week (~one 3 oz. serving/week) would reduce colorectal cancer rates by 7-24% in regions with high intake.  That is, eating red or processed meat once a week likely does not increase risk for colorectal cancer.

At the end of the day, the IARC added processed and red meat to their list of carcinogens.  But in terms of translating that into a public health message, they didn’t do a great job.  Yes, red and processed meats can be hazardous to human health.  But I think we need some research on the quality of red and processed meats.  What are the carcinogenicity profiles of grass fed vs. conventionally raised beef? nitrate-free vs. conventionally processed meats? If you do choose to eat red/processed meats, keep your exposure low and your risk will likely also be low.  As always, eat a varied diet high in fruits and vegetables, whole grains, legumes, nuts and seeds to ensure high antioxidant and anti-inflammatory compound intake to protect against potential damage that red and processed meats may pose.

 

References

  1. Bouvard, et al. on behalf of the International Agency for Research on Cancer Monograph Working Group.  Carcinogenicity of consumption of red and processed meat. Lancet: Oncology. 2015 Dec;16(16):1599-1600.
  2. Chan DS, et al. Red and Processed Meat and Colorectal Cancer Incidence: Meta-Analysis of Prospective Studies. PLoS One. 2011;6(6):e20456.
  3. Norat T, et al. Meat consumption and colorectal cancer risk: dose-response meta-analysis of epidemiological studies. Int J Cancer. 2002 Mar;98(2):241-56.

 

*a version of this post was written by me and originally published on the American Society for Nutrition’s blog.

Image by Dan Edwards on unsplash.com

Review of Whole, by T. Colin Campbell, PhD

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I recently purchased the book Whole: Rethinking the Science of Nutrition.  Based on the title, I knew the book would focus on the importance of eating a diet comprised of whole foods and figured it would be an interesting read.  This book was interesting in the worst kind of way and really just gave me a headache (probably because of all my face-palming. I really only have myself to blame).

T. Colin Campbell, PhD is a nutrition scientist who has been in the field for over fifty years.  Much of his early work focused on liver cancer in rats, but his most notable contribution to the field came from work in China, which led to his book The China Study.  He is an advocate for a whole food, plant based (WFPB) diet, something that I (and nearly all nutritional scientists) support.  But what he means by “whole food, plant based” differs from my definition. I adhere to the school of thought that the foundation of your diet should be plants and unrefined foods; however, Campbell says that your entire diet (or at least 95%) of it should be that. This means no animal products as well as no added sugar, salt, or fat (i.e. taste makers and smile producers).

cover of wholeBut the purpose of Whole was not to discuss the diet that Campbell recommends, specifically.  The China Study goes into that in significantly more detail.  I disagree with the conclusions he drew regarding his work in China and his animal based research, but won’t be able to go into the issues with his scientific approach in any detail here. The purpose of Whole is to describe how nutrition research is carried out and the issues therein.

[Aside: The author of Raw Food SOS, Denise Minger, does an exhaustive review of the issues with the claims made in The China Study that go hand-in-hand with some of the claims made in the documentary Forks Over Knives that I highly recommend reading. Seriously, Denise knocks it out of the park, and I’d like to be her friend. Anyways, one such issue includes using a single animal protein (casein) in an animal model (rat) of only one kind of cancer (liver) and concluding that all animal protein causes cancer. *face, meet palm* Another one includes using the model of A is related to B which is related to C – and spuriously concluding that A causes C (science 101, associations do not equal causation). While I haven’t read the book, I did read one review that said The China Study includes over 8,000 correlations. While I don’t know how many are appropriate, I have a sneaking suspicion that most of them are not grounded in legit statistical approaches.]

Unfortunately, Whole is essentially a 290 page long rant.  The first word I used to describe Campbell in my notes of Whole was “evangelist.” Indeed, at one point he does refer to himself as “enlightened” (red flag!). The book is redundant to the point of exhaustion and is 2-3 fold too long.  Towards the end (ok, middle), I started to simply skip paragraphs and even entire sections that I felt I had already read before.  For most of the book, Campbell’s prose resembles that of a petulant schoolboy who didn’t get picked for the National Institutes of Health’s kickball team and is here to tell you just how unfair the world is. However, amidst the rant, there were some points of clarity with which I really agreed.

  • “Majoring in minor things.” The nutrition science field is obsessed with minutiae.  When we consume a whole food (i.e. a grapefruit), there are many nutrients in that food. There are vitamins, minerals, sugars, phytochemicals, etc., but many nutrition studies only focus on a single nutrient.  This is an issue because nutrients act in synergistic ways and affect nearly every tissue in the body, which makes food difficult to study.  Campbell points out that “virtually nothing in biology is as precise as we try to make it seem” (pg. 11).  I only sort of agree with that point, because almost everything in biology is extremely precise, but how we study biology and how nutrients impact our biology is not as well understood as many people think/pretend.  For example, it is extremely difficult to quantify nutrient absorption and delivery to tissues, let alone determine the nutrient content of a given food, which depends on season, soil conditions, harvesting, storage conditions, etc.  Colin seems to find no utility in the kind of research that attempts to parse these concepts out, which I do not agree with (more on that in a minute).  Just because we haven’t figured out how to do those studies yet doesn’t mean we should never try.  He seems to think we shouldn’t.
  • We shouldn’t eat so many animals and things that come from animals. Agreed. For the sake of our health, our planet’s health, the economy, and so on, we should eat less meat.  While he claims that his beliefs have been met with resistance from other people in the field, I’ve never met a nutrition scientist that would argue with this idea.  The resistance likely comes from his assertions that veganism is the only means to achieve health because (1) it’s not and (2) the data don’t support the idea that it is.  But eat less meat? Yes. Definitely.
  • Money corrupts everything. Probably not, but it’s not far from the truth.  Industry (food, supplement, pharmaceutical companies) provides a lot of funding to health regulatory bodies and also have some pretty powerful lobbyists that to drive health policy in a way that supports their bottom line.  This doesn’t make them inherently evil and untrustworthy, but it does require that we are aware of their presence and understand how powerful they can be. And you can bet on the fact that no matter what their message, they are concerned about profit more than human health. Campbell spends a third of the book saying just that.  While I think it’s important to recognize this, I also think that it’s important to figure out how to work within a capitalistic system in order to get our messages about health heard.  We can shake our fists at corporations and the system, or we can form partnerships with the ones that have products that actually do have a place in a healthy lifestyle and use that as a platform to get our messages out there.  Maybe I’m naive, but I don’t think it has to be as doom and gloom as Campbell alleges.

Outside of those few items, I took issue with essentially the rest of the book. While there are only a few bullet points here, I do feel like all of this should be underlined, bolded, and probably written in caps lock. But I didn’t write it that way because I know no one wants to read that.

  • Reductionism. If I had the time or energy, I’d like to count how many times Campbell used this word in the book.  It was obnoxious.  Reductionism is the practice of taking a complex system and breaking it down into individual parts in an attempt to understand it at its most basic level. Campbell abhors it and not entirely without reason.  I, myself, have to shake my head at some reductionist science due to the old adage of “losing sight of the forest for the trees.” That is, getting bogged down in the details of something that ultimately doesn’t matter.  But that isn’t inherent or exclusive to reductionist approaches to science. That happens at all levels of science. Campbell goes so far as to say that reductionism is “wearing the guise of science,” which is absolutely ridiculous.  It is science. It is one approach to science, and is an essential piece to understanding the whole (you know, the topic of the book). While scientists can lose sight of this, that doesn’t mean an entire approach should be vilified. An issue that happens in all approaches to science is making broad stroke claims about findings in order for the impact of one’s work to look much greater than it is.  Scientists who make these kinds of inappropriate conclusions, the peer reviewers who don’t catch them, and the journals that subsequently publish them are the issue, not the science in and of itself.  In my opinion, this underscores the importance of a better, more stringent peer review system than anything.
    One of the more comical things that I noticed while reading Whole was that Campbell spent nearly the entire book harping on reductionism, but then explained molecular concepts in nutrition, metabolism and disease that we understand solely because reductionist methodology was employed to study these processes. *face palm*
  • The Scientific Method. There were times reading Whole that I flipped from being flabbergasted to angry.  Again, in his crusade against reductionism, Campbell attacks pretty much all types of science other than observational studies. A lot of scientists have big egos and they think that their type of science is the absolute best and most important. I typically have to laugh at this because the truth is that all general approaches to science are important. Observational or epidemiological studies determine trends in health and disease, basic or reductionist science aims to determine the how and why, and randomized controlled trials intervene by changing a behavior or providing a treatment to a human with the goal of modifying health.  Campbell seems to believe that observational science is the only science that matters, which is not only incorrect, but also harmful if his readers now believe that.
  • No means of change. While Campbell spends close to 300 pages bemoaning the state of research and health in America, he misses an opportunity to actually teach people. He throws information at the reader, but at the end of the book, the reader is likely left feeling a little lost and hopeless. Campbell attacks the National Institutes of Health, the American Cancer Society, the American Society for Nutrition, the Academy of Nutrition and Dietetics, and so on. So whom should consumers trust? What I find most unfortunate about this book is that he provides no tools or resources for his readers. They’ve likely come to believe that they can’t trust anyone, but is that actually true and what good does that do? He had such a golden opportunity to teach people how to think critically and thoughtfully about the science presented in the media that they will encounter, but he didn’t. He also didn’t provide an organization or a group that consumers can trust. After reading this book, I think most readers are only slightly more informed than they were before starting it, but they are more than likely just very frustrated. That is, if they can manage to get through the whole thing.

Final Grade: C

Bottom Line: If you happen to come across this book, skip the entire thing except for the last chapter called “Making Ourselves Whole.” It’s only five pages long and it provides a nice summary, written in the most moderate, reasonable prose of the entire book. In fact, after spending the whole book complaining about reductionism, Campbell finally says what he should have said all along: “…we must stop seeing reductionism as the only method by which to achieve progress and start seeing it as a tool, the results of which can only be properly evaluated within a wholistic framework.” – pg. 286
If you decide to read the entire thing, take it with a grain of salt and be sure to read other works on the topic.

Better than Butter? Not Sugar

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The battle against saturated fat continues.  In the past, it was considered nutritional dogma that saturated fats should be limited in order to preserve or restore cardiovascular health.  However, in recent years, this has been called into question as some studies have found no association between intake and risk for coronary heart disease (CHD) (1).

Recent work out of the Harvard School of Public Health may bring some more clarity to this question (2).  An important issue when considering how we limit certain nutrients is with what we are replacing said nutrient.  This is important because people typically don’t just stop eating a lot of calories of one nutrient without replacing it with something different.  Many studies are unable or do not consider this in their analysis or study design.

Using data from over 120,000 adults enrolled in the Health Professional’s Follow-up Study and the Nurse’s Health Study, Li, et al. evaluated diet over time.  After 24-30 years of follow-up, over 7,000 cases of CHD (defined as death from CHD or heart attack) were reported.  Interestingly, those who had the highest intake of polyunsaturated fatty acids (PUFAs; think: vegetable oils, fish, nuts, seeds) or high quality carbohydrates (think: whole grains, quinoa, beans) had a significantly reduced risk of developing CHD compared to those who had the lowest intake.

But regarding saturated fat, when 5% of intake was replaced with either PUFAs, whole grains, or monounsaturated fatty acids (think: olive oil, avocados, nuts), risk for developing CHD dropped by 9-25%, with PUFAs being the most beneficial.  However, if saturated fats were replaced with trans fats or refined carbohydrates (think: sugar, white bread/rice/pasta/crackers, etc.), there was no change in risk for CHD.

This analysis is unique because the study was able to determine nutrient intake over time. Many studies simply have dietary data at one time point and correlate that with some outcome years and maybe even decades down the line.  This is an issue because diet may change over time and, because of that, these analyses may be subject to drawing false conclusions.  However, because this study was able to evaluate diet over time, it could determine the effect of changes in diet (i.e. replacing 5% of saturated fat with another nutrient).

Furthermore, it tells us why previous studies may not have been able to detect a role of saturated fat on CHD risk.  Hypothetically, consider this scenario: two people have heart attacks. Person 1 ate less saturated fat than person 2, but he/she ate more refined carbs/trans fats than person 2.  A general analysis would tell us that saturated fats aren’t necessarily the problem.  This study by Yi, et al. takes that a step further and shows us that refined carbohydrates, saturated fat, and trans fats are all associated with relatively equal risk of CHD.  However, calorie for calorie, if you replace the butter or cheese with vegetable oils, nuts, beans, quinoa (or a host of other healthy fats and carbohydrates!) you could be saving yourself from some heart trouble down the line.

Read about the study by Li, et al. here.

References
1. Chowdhury R, et al. Association of dietary, circulating, and supplement fatty acids with coronary risk: a systematic review and meta-analysis. Ann Intern Med 2014;160: 398–406

2. Li Y, et al. Saturated fats compared with unsaturated fats and sources of carbohydrate in relation to risk of coronary heart disease: a prospective cohort study.  J Am Coll Cardiol 2015;66(14):1538-48.

 

Image from unsplash.com by Juan Jose Valencia Antia.