How about a serving of fish with that anti-depressant? The idea that what you eat could influence the development and even treatment of depression is gaining ground. WSJ's Sumathi Reddy and Tanya Rivero discuss a new study showing the psychological benefits of a modified Mediterranean diet. Photo: iStock

Yes, it exists.

Science says there's a way to eat as much as you want, and easily stop when you're full.

Which means you can ditch that restrictive diet that demands you count every calorie.

A new study published in the journal Obesity compared the Mediterranean diet to the typical Western diet.

Scientists at the Wake Forest School of Medicine found that nonhuman primates on a Mediterranean diet wouldn't eat all the food available to them and maintained their weight. The animals on a Western diet overate and gained weight.

The diets in the study were carefully designed to reflect human diets.

In the Mediterranean diet, protein and fat were derived largely from plant sources while the Western diet used animal sources.

Both diets had comparable amounts of fat, protein and carbs.

"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," says the study's principal investigator, Carol A Shively.

And they had less chance of non-alcoholic fatty liver disease (NAFLD), seeing as obesity is one of the main causes of NAFLD.

The 38-month prevention trial was the equivalent of studying the same effect in humans for over nine years.

Shivlely says this is the first preclinical trial to measure the effects of long-term Western versus Mediterranean diets on obesity-related diseases under controlled conditions. Self-reported data on caloric intake is often unreliable.

"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 over-consume. Eating a Mediterranean diet should allow people to enjoy their food and not overeat,” Shively says.

"We hope our findings will encourage people to eat healthier foods that are also enjoyable, and improve human health."