Obesity is so rare among those eating plant-based diets (see my video Thousands of Vegans Studied), nutrition researchers have been desperate to uncover their secret. Yes, they tend to eat fewer calories, but not that many fewer. In the past I've made videos about a couple of the theories that have emerged. Maybe because people eating plant-strong diets express more of the fat shoveling enzyme inside the power plants--the mitochondria-within our cells (How to Upregulate Metabolism). Maybe it's because they grow different populations of good bacteria in their gut (Gut Flora & Obesity). Maybe it's because they're avoiding the endocrine disrupting industrial pollutants in the meat supply. An Obesity-Causing Chicken Virus may even be contributing. We're still not sure, but the theories keep coming.
Maybe it's the propionate, an anti-obesity compound made by our gut bacteria when we feed them fiber. Watch my 2-min. video Fawning Over Flora for details.
Our friendly flora's digestion of fiber also yields another short chain fatty acid called butyrate, which appears to protect against colon cancer. Butyrate may also explain why fiber-filled plant-based diets are so anti-inflammatory. A recent review concluded that "butyrate seems to exert broad anti-inflammatory activities and might be [a] good candidate to evaluate in the fight against obesity-associated and systemic inflammation in general." See my coverage of that review in my 1-min. video Boosting Good Bacteria in the Colon Without Probiotics.
Since butyrate is a byproduct of fiber digestion, we can boost its production by eating more plant foods, and we can boost the number of butyrate-producing bacteria in our colon by really eating more plant foods-those eating vegetarian harbor more butyrate-producing bacteria.
For more on fabulous fiber, see What Women Should Eat to Live Longer and Relieving Yourself of Excess Estrogen. For a sampling of my other videos on keeping your colon happy, see Kiwifruit For Irritable Bowel Syndrome, Flax and Fecal Flora, and Bristol Stool Scale.
-Michael Greger, M.D.
Image credit: Joey Yee / Flickr