Obesity is strongly associated with metabolic alterations and negative health outcomes including diabetes, cardiovascular disease, and some types of cancer (1, 2, 3, 4). Excess body fat is one of the primary causes of preventable health problems and mortality in the United States and many other affluent nations, ranking in importance with cigarette smoking and physical inactivity. Obesity is thought to contribute to disease via the metabolic disturbances it causes, including excess glucose and lipids in the circulation, dysregulated hormone activity including insulin and leptin, and inflammatory effects. This immediately raises two questions:
Does metabolically healthy obesity exist?
If so, are metabolically healthy obese people at an elevated risk of disease and death?
As we continue to explore the foods our ancestors relied on during our evolutionary history, and what foods work best for us today, we come to legumes such as beans and lentils. These are controversial foods within the Paleolithic diet community, while the broader nutrition community tends to view legumes as healthy.
Beans and lentils have a lot going for them. They're one of the few foods that are simultaneously rich in protein and fiber, making them highly satiating and potentially good for the critters in our colon. They're also relatively nutritious, delivering a hefty dose of vitamins and minerals. The minerals are partially bound by the anti-nutrient phytic acid, but simply soaking and cooking beans and lentils typically degrades 30-70 percent of it, making the minerals more available for absorption (Food Phytates. Reddy and Sathe. 2002). Omitting the soaking step greatly reduces the degradation of phytic acid (Food Phytates. Reddy and Sathe. 2002).
The only tangible downside to beans I can think of, from a nutritional standpoint, is that some people have a hard time with the large quantity of fermentable fiber they provide, particularly people who are sensitive to FODMAPs. Thorough soaking prior to cooking can increase the digestibility of the "musical fruit" by activating the sprouting program and leaching out tannins and indigestible saccharides. I soak all beans and lentils for 12-24 hours.
The canonical Paleolithic diet approach excludes legumes because they were supposedly not part of our ancestral dietary pattern. I'm going to argue here that there is good evidence of widespread legume consumption by hunter-gatherers and archaic humans, and that beans and lentils are therefore an "ancestral" food that falls within the Paleo diet rubric. Many species of edible legumes are common around the globe, including in Africa, and the high calorie and protein content of legume seeds would have made them prime targets for exploitation by ancestral humans after the development of cooking. Below, I've compiled a few examples of legume consumption by hunter-gatherers and extinct archaic humans. I didn't have to look very hard to find these, and there are probably many other examples available. If you know of any, please share them in the comments.
To be clear, I would eat beans and lentils even if they weren't part of ancestral hunter-gatherer diets, because they're inexpensive, nutritious, I like the taste, and they were safely consumed by many traditional agricultural populations probably including my own ancestors.
Extensive "bean" consumption by the !Kung San of the Kalahari desert
Jonathan Bailor recently released an interview we did a few months ago on the neurobiology of body fat regulation, and the implications for fat loss. It's a good overview of the regulation of food intake and body fatness by the brain. You can listen to it here.
Super Human Radio
Carl Lanore interviewed me about my lab's work on hypothalamic inflammation and obesity. I'm currently wrapping up a postdoctoral fellowship with Dr. Michael Schwartz at the University of Washington, and the interview touches on our recent review paper "Hypothalamic Inflammation: Marker or Mechanism of Obesity Pathogenesis?" Dan Pardi and I are frequent guests on Carl's show and I'm always impressed by how well Carl prepares prior to the interview. You can listen to the interview here.
The Reality Check podcast
Pat Roach of the Reality Check podcast interviewed me about the scientific validity of the "carbohydrate-insulin hypothesis" of obesity. The Reality Check podcast "explores a wide range of controversies and curiosities using science and critical thinking", and a dash of humor. This one should be very informative for people who aren't sure what to believe and want a deeper perspective on the science of insulin and body weight regulation. You can listen to it here.
Obesity Society conference
Next Thursday 11/9, I'll be speaking at the 2013 Obesity Society conference in Atlanta. My talk is titled "The Glial Response to Obesity is Reversible", and it will be about my work on the reversibility of obesity-associated hypothalamic neuropathology in mice. My talk will be part of the session "Neuronal Control of Satiety" between 3:00 and 4:30, specific time pending. See you there!
One of my most popular posts of all time was a recipe I published in 2010 for sourdough buckwheat crepes (1). I developed this recipe to provide an easy, nutritious, and gluten-free alternative to flour-based crepes. It requires no equipment besides a blender. It's totally different from the traditional buckwheat crepes that are eaten in Brittany, in part because it's not really a crepe (I don't know what else to call it, maybe a savory pancake?). I find these very satisfying, and they're incredibly easy to make. They're especially delicious with fresh goat cheese, or scrambled eggs with vegetables, but they go with almost anything. Chris Kresser also developed his own version of the recipe, which is fluffier than mine, and more like a traditional pancake (2).
Buckwheat is an exceptionally nutritious pseudograin that's rich in complete protein and minerals. In contrast to most whole grains, which have low mineral availability due to phytic acid, buckwheat contains a high level of the phytic acid-degrading enzyme phytase. This makes buckwheat an excellent source of easily absorbed minerals, as long as you prepare it correctly! Phytase enzyme works best in an acidic environment, which may be part of the reason why so many cultures use sour fermentation to prepare grain foods. My original recipe included a sour fermentation step.
But there's a problem here. Buckwheat doesn't ferment very well. Whether it's because it doesn't contain the right carbohydrates, or the right bacteria, I don't know, but it spoils rapidly if you ferment it more than a little bit (using a strong sourdough starter helps though). Others have told me the same. So here's my confession: I stopped fermenting my buckwheat batter about a year ago. And it tastes better.
Yesterday, the Dan's Plan blog Eat Move Sleep published a blog post I wrote about sleep, artificial light, your brain, and a free computer program called f.lux that can help us live healthier lives. Head over to Eat Move Sleep to read it.
Evidence is steadily accumulating that insufficient sleep increases the risk of obesity and undermines fat loss efforts. Short sleep duration is one of the most significant risk factors for obesity (1), and several potential mechanisms have been identified, including increased hunger, increased interest in calorie-dense highly palatable food, reduced drive to exercise, and alterations in hormones that influence appetite and body fatness. Dan Pardi presented his research at AHS13 showing that sleep restriction reduces willpower to make healthy choices about food.
We also know that genetics has an outsized influence on obesity risk, accounting for about 70 percent of the variability in body fatness between people in affluent nations (2). I have argued that "fat genes" don't directly lead to obesity, but they do determine who is susceptible to a fattening environment and who isn't (3). I recently revisited a 2010 paper published in the journal Sleep by University of Washington researchers that supports this idea (4).