Vegans are stereotypically skinny. But according to Neal Barnard, MD and his research team, it may not be because their diets are nutritionally skimpy. Vegan bodies may just learn to burn calories faster.
Dr. Barnard, who’s the founding president of the Physicians’ Committee for Responsible Medicine (PCRM) and a professor at George Washington School of Medicine and Health Sciences, noticed that in one of his studies, after transitioning a group of individuals with chronic weight problems onto an entirely plant-based diet that was low in added vegetable oils, their metabolic rates (or how fast their body turned fuel into energy) seriously soared.
“We found that not only did their calorie-burning speed jump up after a meal—but that extra burn was significantly higher than it had been when the study started,” Dr. Barnard writes in his book, The 21-Day Weight Loss Kickstart.
To find out why this had happened, Dr. Barnard peeked inside some muscle cells and came up with this theory: Insulin escorts sugar and protein from your bloodstream into your cells, where calorie-burning mitochondria metabolize (or burn) fat.
“We found that not only did their calorie-burning speed jump up after a meal—but that extra burn was significantly higher than it had been when the study started.”
But in people with high-fat, meaty diets, tiny fat droplets crowd the cell and inhibit the insulin’s ability to shoot the nutrients in. It’s like a highway during rush hour: the commuters are fat droplets, and you, the insulin, are just trying to get your car moving down the freeway so that you can get to work.
What does this have to do with burning calories?
“You want to get sugar out of your blood and into your cells,” says Susan Levin, MS, RD, the director of nutrition education at PCRM. “The less fat there is, the faster this process happens.”
If the sugar can’t get into the cells, your body can’t convert it into energy fast enough, and it starts storing it. This is what happens if a cheeseburger is your go-to snack.
Vegans eat mostly plants, grains, and legumes, which are just generally way lower in fat than animal products. So, their cells are clear of metabolism-slowing fat globules. A vegan’s mitochondria burn fat at the speed of the Acela train.
So is it worth changing your diet (rather than your personal trainer)? It will certainly be less painful than upping your burpee reps. “You could pretty comfortably assume that if you change from a high-fat diet to a low-fat diet full of plant-based whole-foods, right away your cells are going to be able to function better,” says Levin.
And high-functioning cells equal a humming metabolism; your cells will be burning broccoli at lightning speeds.
If you’re vegan and have already worked your way through these 10 popular cookbooks, here are three mindblowing plant-based dishes from the trainer who inspired Beyonce to go vegan.
Originally posted March 1, 2012. Updated January 18, 2016.