We know vegetarians have considerably lower obesity rates compared to meat-eaters, but why? Is it because they’re not eating meat, or because they’re eating more plants? Or maybe they’re just eating fewer calories, or exercising more? This study controlled for all that.

In essence, they took men and women who ate the same number of calories a day, ate the same amount of vegetables, and fruit and grains, same amount of exercise—but, ate different amounts of meat. Men and women who ate less than a single serving of meat a day were, on average, not overweight, but the more meat they ate, the heavier they were, and by one and a half servings a day, they crossed the threshold of a BMI of 25 to become officially classified as overweight.

Which type of meat was the worst? If you remember back to that study of hundreds of thousands of men and women, poultry consumption appeared to be the worst, but maybe it was reverse causation, meaning obesity led to greater chicken consumption, and not the other way around. This new study controlled for that, adjusting for dietary habits, yet found the same thing. Chicken consumption was most associated with weight gain in both men and women. And it didn’t take much. Compared to those who didn’t eat any chicken at all, those eating about 20 or more grams of chicken a day had a significantly greater increase in their body mass index. That’s around one chicken nugget. Or a single chicken breast once every two weeks, compared to no chicken at all.

To see any graphs, charts, graphics, images, and quotes to which Dr. Greger may be referring, watch the above video. This is just an approximation of the audio contributed by Katie Schloer.

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