Plant-Based Diets: Strategies for Overweight Adults


It’s no secret that being overweight or obese may predispose those individuals to associated diseases – particularly type 2 diabetes, metabolic syndrome, and cardiovascular disease. It’s uncommon to find individuals, who follow plant-based diets in that cohort – due to the high-fiber, low-fat content of vegan-style eating strategies – in conjunction with the increased thermal effect of these diet plans, which accounts for approximately 10% of the toral energy expenditure.

Another feature of the vegan-type diets is its reduction of both muscle and liver fat, while increasing mitochondrial (energy burning) and postprandial (after eating) metabolisms. Just how successful have these diet strategies been for overweight adults, is food for thought for researchers.

In November of 2020, JAMA Network Open reported the results of an original investigation – Effect of a Low-Fat Vegan Diet on Body Weight, Insulin Sensitivity, Postprandial Metabolism, and Intramyocellular and Hepatocellular Lipid Levels in Overweight Adults, which concluded that, “a low-fat plant-based dietary intervention reduces bodyweight by reducing energy intake and increasing postprandial metabolism. The changes are associated with reductions in hepatocellular (liver) and intramyocellular (muscle) fat and increased insulin
sensitivity.”

The study authors, from Physicians Committee for Responsible Medicine (Washington, DC), Yale School of Medicine (New Haven, Conn.), CNR Institute of Neuroscience (Padua, Italy), Institute of Endocrinology (Prague, Czech Republic), University of Utah (Salt Lake City), and George Washington University School of Medicine & Health Sciences (Washington, DC), recruited 244
participants between January 2017 and February 2019 in Washington, DC., to participate in a 16 week- randomized clinical trial.

Enrollment included adults between 25 and 75 years old – with a body mass index between 28 (overweight) and 40 (obese).

Those participants in the intervention group followed a vegan diet composed of approximately 75% of the energy from carbohydrates, 15% protein, and 10% fat – which took the form of vegetables, grains, legumes, and fruits. The eating plan was devoid of animal products or added fats.

The control diet group was asked to make no changes to their standard diet, while both groups limited alcohol consumption to 1 drink for women and 2 for men. Both groups were asked to maintain their current exercise level and medication, unless changed by their personal physician. At baseline and at study conclusion, 3-day dietary intake assessments were analyzed, appropriate laboratory assessments were completed, after an overnight fast – along with height, weight, body composition and visceral fat determinations assessed.

At the study conclusion, the researchers found, “the dietary intervention reduced body weight, apparently owing to its tendency to reduce energy intake and increase postprandial energy expenditure. The intervention also improved glycemic control and reduced insulin concentrations, owing in part to reduced lipid accumulation in liver and muscle cells and thus reduced insulin resistance in these organs.” It also appears that this research also validated prior research. “The present finding that the increase in thermic effect of food was associated with decreased fat mass
and increased insulin sensitivity confirm the findings of previous research,” which led the researchers to state that, “this intervention may be an effective treatment for overweight adults.”

Interested in Listening to a Podcast? Check Out Maximum Wellness, Episode 101: How Men Accumulate Visceral Abdominal Fat