On Jan. 21, 2021, the National Institutes of Health announced results of a small but highly controlled study that indicated people on a low-fat, plant-based diet ate fewer daily calories but had higher insulin and blood glucose levels, compared to when they ate a low-carbohydrate, animal-based diet.

The study compared the effects of the two diets on calorie intake, hormone levels, body weight, and more. The findings were published in Nature Medicine.