Mediterranean diet may prevent overeating, study says
Individuals on a Mediterranean diet may be able to manage weight and avoid overeating, according to a new study published today in the journal Obesity.
Researchers from Wake Forest Baptist Medical Center in Winston-Salem, North Carolina looked at nonhuman primates over 38 months who consumed either a Western or Mediterranean diet. The two diets were formulated to closely reflect human diets with protein and fat derived largely from animal sources in the Western diet and primarily from plant sources in the Mediterranean diet. The diets contained similar proportions of fat, protein, and carbohydrates, the study said.
In the randomized, preclinical, primary prevention trial, 38 middle-aged females were randomly assigned to either the Mediterranean or Western diet. Both groups were matched on their baseline weight and body fat and could eat as much as they wanted throughout the study.
The researchers found that the group on the on the Mediterranean diet ate fewer calories, had lower body weight, and had less body fat than those on the Western diet, according to Carol Shively, PhD, professor of pathology at Wake Forest School of Medicine and principal investigator.
"By comparison, the animals on a Western diet ate far more than they needed and gained weight," she said in a statement.
Shively said this is the first preclinical trial to measure the effects of long-term consumption of a Western versus Mediterranean diet on obesity-related diseases under controlled experimental conditions. Previous research on the effects of diet type on caloric intake was largely based on human population studies that relied on self-reported food intake, which is often unreliable, or rodent studies with nonhuman-type diets, she said.
The findings provide the first experimental evidence that a Mediterranean diet protected against increases in consumption, obesity, and prediabetes when compared to a Western diet. However, the results are limited by the modest sample size, researchers say, and will require larger samples and human trials in the future.
The Mediterranean diet also protected against non-alcoholic fatty liver disease (NAFLD), a condition that can cause cirrhosis of the liver and liver cancer and require a transplant. Obesity is a major cause of NAFLD. By 2030, one-third of adults in the U.S. will have the disease, which is the fastest growing reason for liver transplants in young adults in the country, according to the American Liver Foundation.
"Diet composition is a critically important contributor to the U.S. public health, and unfortunately those at the greatest risk for obesity and related costly chronic diseases also have the poorest quality diets," Shively said. “Eating a Mediterranean diet should allow people to enjoy their food and not overeat. We hope our findings will encourage people to eat healthier foods that are also enjoyable and improve human health."