Plant-based diet increases post-meal metabolism, study says

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A plant-based diet boosts after-meal calorie burn, leads to weight loss, and improves cardiometabolic risk factors in overweight individuals, according to a new randomized control trial by researchers with the Physicians Committee for Responsible Medicine and published in the journal JAMA Network Open.

For the study, researchers randomly assigned participants, who were overweight and had no history of diabetes, to an intervention or control group in a 1:1 ratio. For 16 weeks, participants in the intervention group followed a low-fat, plant-based diet based on fruits, vegetables, whole grains, and legumes with no calorie limit. The control group made no diet changes. Neither group changed exercise or medication routines, unless directed by their personal doctors.

Researchers used indirect calorimetry to measure how many calories participants burned after a standardized meal at both the beginning and end of the study. The plant-based group increased after-meal calorie burn by 18.7 percent, on average, after 16 weeks. The control group's after-meal burn did not change significantly, according to the study.

Within just 16 weeks, participants in the plant-based group lowered their body weight by about 14 pounds, on average, compared to an insignificant change in the control group. The plant-based group also saw significant drops in fat mass and visceral fat volume, the dangerous fat found around the internal organs, the researchers said.

Additionally, the plant-based group decreased their fasting plasma insulin concentration by 21.6 pmol/L, decreased insulin resistance, and increased insulin sensitivity, while the control group saw no significant changes. The plant-based group also reduced total and LDL cholesterol by 19.3 mg/dL and 15.5 mg/dL, respectively, with no significant changes in the control group, according to the study.

"These findings are groundbreaking for the 160 million Americans struggling with overweight and obesity," said Hana Kahleova, MD, PhD, study author and director of clinical research for the Physicians Committee for Responsible Medicine, in a statement. "Over the course of years and decades, burning more calories after every meal can make a significant difference in weight management."