High-Fat Mediterranean Diet Does Not Cause Weight Gain

A Mediterranean diet rich in healthy fats can prevent weight gain, a study published Monday has announced.

The study, published by the Lancet Diabetes and Endocrinology journal and conducted by Primary Prevention of Cardiovascular Disease with a Mediterranean Diet (PREDIMED) in Spain, found that over a five-year period, a high-fat diet that emphasizes healthy food sources such as olive oil and nuts was more successful in keeping weight off than a low-fat diet.

The study was conducted between 2003 and 2011 and involved nearly 7,500 participants ranging in age from 55 to 80. All participants had either a high risk for heart disease or Type II Diabetes. Over 90 percent of participants were overweight or obese.

Participants were divided into three groups and assigned differing diets. The first group ate a calorie-unrestricted Mediterranean diet rich in olive oil; the second also ate an unrestricted-calorie Mediterranean diet but supplemented their diet with nuts instead. The third group ate a low-fat diet.

Participants in all three groups lost weight at the conclusion of the study. Those in the olive oil group lost on average of nearly two pounds. Those in the low-fat group lost 1.3 pounds on average, and the nut group lost 0.9 pounds on average.

All participants had some growth in waist circumference, but those in the high-fat groups had less growth than those in the low-fat group.

The study sheds new light on the role that fat plays in health and weight management.

“The fat content of foods and diets is simply not a useful metric to judge long-term harms or benefits,” wrote Professor Dariush Mozaffarian, who teaches at the School of Nutrition Science and Policy at Tuft University, in a comment piece attached to the study.

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“They don’t have caveats with fruits and vegetables but do with fat,” he added. “And this study shows we should get rid of that fear of fat.”

The professor cited another study he had participated in that replaced carbs with cheese and found that participants experienced no weight gain and a decreased risk of developed diabetes.

“Healthy foods are healthy foods, and bad foods are bad,” Mozaffarian said. “It doesn’t matter if the food is low fat or high fat. This is a separate issue.”

Dr. Ramon Estruch, lead author of the study and scientist at the Spanish Biomedical Research Center at the University of Barcelona, concurs with Mozaffarian’s assessment.

“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,” he said. “Our study shows that a Mediterranean diet rich in vegetable fats such as olive oil and nuts had little effect on body weight or waist circumference compared with people on a low-fat diet. The Mediterranean diet has well-known health benefits and includes healthy fats such as vegetable oils, fish and nuts.”

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Organizations across the globe have long recommended a low-fat diet to maintain health and a healthy weight. The World Health Organization recommends that no more than 30 percent of caloric intake come from fats in order to avoid weight gain. The American Heart Association suggests opting for low-fat dairy products and a general restriction of saturated fats, which are found in nuts.

The release of the study results is another blow to the low-fat ideology, which modern nutritionists like Mozaffarian are openly rejecting as outdated and harmful.

“Modern scientific evidence supports an emphasis on eating more calories from fruits, nuts, vegetables, beans, fish, yoghurt, phenolic-rich vegetable oils, and minimally processed whole grains; and fewer calories from highly processed foods rich in starch, sugar, salt, or trans-fat,” Mozaffarian wrote in his comment piece.

“We ignore this evidence – including these results from the Predimed trial – at our own peril.”

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