Surprising new study – Mediterranean diet does not cause weight gain even though high in fat

A new study from the University of Barcelona in Spain has determined that a Mediterranean diet, although rich in vegetable fats like nuts and olive oil, does not cause weight gain, and has little effect on waist circumference or body weight when compared with low-fat diets. Although high in fats, the Mediterranean diet includes what the researchers call “healthy fats,” from fish and vegetables, rather than the saturated fats found in butter and red meat.

The study, published in The Lancet Diabetes and Endocrinology journal, states that, although the Mediterranean diet includes foods that are high in fat, it does not include many foods associated with weight gain, such as sweets, fast food, processed meat and sugary beverages.

The study included more than 7,000 people between the ages of 55 and 80, 90 percent of whom were overweight. Participants were randomly assigned to one of three groups. One group ate a low-fat diet and were given non-food gifts every three months, such as spoons or kitchen clocks. The other two groups followed an unrestricted-calorie Mediterranean diet. One group ate extra virgin olive oil and were given 1 liter per week for themselves and their families. The third group followed an unrestricted-calorie Mediterranean diet with added nuts, and received a gift of 15g of walnuts, 7.5g of hazelnuts, 7.5g of almonds and 1kg of mixed nuts every three months.

Weight loss was not substantial in any of the groups. However, it was greatest in the group that followed the Mediterranean diet with olive oil. Although all three groups increased their weight measurements, thought to be a normal part of the aging process, the smallest increase was in the group eating a Mediterranean diet with added nuts.

The researchers think that the fear of fat is misplaced, and that guidelines restricting fat in diets is wrong, and believe their results should bring back the Mediterranean diet and its known health benefits. Lead study author Dr. Ramon Estruch said, “More than 40 years of nutritional policy has advocated for a low-fat diet but we’re seeing little impact on rising levels of obesity.”

Estruch said the study shows that a Mediterranean diet has little effect on waist circumference or body weight, although rich in vegetable fats. He cautioned, however, that the findings do not imply that “unrestricted diets with high levels of unhealthy fats such as butter, processed met, sweetened beverages, desserts or fast-foods are beneficial.”