The Mediterranean diet could be the key to tackling obesity as new research found it stops bingeing and helps to maintain a healthy weight.
The diet, common to countries in southern Europe, involves eating more fruits, vegetables, fish and whole grains while limiting red meat and replacing butter with healthier olive oil.
Nonhuman primates who were put on this healthy diet chose not to eat all the food available to them and maintained a normal weight.
Scientists studied the animals for 38 months which is equivalent to about nine years for humans.
The diets were made to closely reflect human diets. In the Western diet, protein and fat came largely from animal sources and from plant sources in the Mediterranean diet.
The two diets contained comparable proportions of fat, protein and carbohydrates.
There were 38 middle-aged females in the study which were randomly put on either the Mediterranean or Western diet.
The groups were matched on their baseline weight and body fat and were allowed to eat as much as they wanted throughout the study.
The research, by the Wake Forest School of Medicine in North Carolina experimentally proves that a Mediterranean diet stopped binge eating, obesity and prediabetes compared to a Western diet.
The Mediterranean diet also protected against non-alcoholic fatty liver disease (NAFLD) which can cause liver cancer.
Obesity is a major cause of NAFLD, the fastest growing reason for liver transplants in young adults in the US.
Professor Carol Shively said: “By comparison, the animals on a Western diet ate far more than they needed and gained weight.
“What we found was that the group on the Mediterranean diet actually ate fewer calories, had lower body weight and had less body fat than those on the Western diet.
“Diet composition is a critically important contributor to the US public health and unfortunately those at the greatest risk for obesity and related costly chronic diseases also have the poorest quality diets.
“The Western diet was developed and promoted by companies who want us to eat their food, so they make it hyper-palatable, meaning it hits all our buttons so we overconsume.
“Eating a Mediterranean diet should allow people to enjoy their food and not overeat, which is such a problem in this country.
“We hope our findings will encourage people to eat healthier foods that are also enjoyable, and improve human health.”
This is the first preclinical trial to compare the effects of long-term consumption of Mediterranean and Western diet on obesity-related diseases.
Previous research on the effects of diet on calorie intake was largely based on human population studies that relied on people reporting the amount of food they eat, which is often unreliable, or studies on mice or rats with nonhuman diets.
The research was published in the April 23 issue of the journal Obesity.