This Kind of Fat Won’t Make You Gain Weight

Health experts have warned for years that eating too much fat can contribute to calorie overload, overweight and obesity. But not all fats are created equal, and in the latest study on the subject, scientists found that eating certain fats, no matter how many calories they contain, won’t lead to significant weight gain.

In the study published in the journal Lancet Diabetes & Endocrinology, researchers in Spain report that people who were put on a Mediterranean diet without any calorie restrictions for five years lost slightly more weight than people put on a low-fat diet for the same amount of time.

The group of 7,447 middle-aged men and women, who were at higher risk of having heart problems because they had type 2 diabetes or other heart-related risk factors, were mostly overweight or obese. Those who were told to adopt a Mediterranean diet, which contains more fresh fruits and vegetables and lean proteins like fish, also added either olive oil or nuts to their diet, but they did not restrict the number of calories they ate. The control group was told to eat a low-fat diet and also weren’t limited in the amount of calories they ate daily.

The findings highlight the more sophisticated understanding that nutrition and health experts have about the role of fats in promoting health. Advice to limit or eliminate fatty foods can backfire for health, since people tend to replace the fats from meats or proteins with carbohydrates and sweets, which can be just as detrimental (if not more) for promoting obesity and heart disease.

Recent studies have found similar results that question the damning of all fats. One study revealed that only 3.6% of heart deaths around the world can be attributed to saturated fats found in red meat and dairy products, while more than 10% of heart deaths were traced to eating too few plant oils, like those that are plentiful in a Mediterranean diet. In another study by the same authors of that analysis, people who drank full-fat milk had a 46% lower risk of developing diabetes than those who chose skim.

The Spanish researchers found that people on the Mediterranean diet also ate more vegetables, fruit and fish and consumed less meat and dairy products than those on the low-fat diet. That could explain why, even though they weren’t told to eat fewer calories, the people in the Mediterranean group tended to lose slightly more weight than those in the low-fat group.

Taken together, these results and those from other recent studies are making a stronger case against cutting out all fat from the diet. Good fats, such as those from plants like olive oil and nuts, are not only helpful for the heart but won’t add to weight gain. And keeping a healthy weight is yet another way to avoid problems like heart disease and diabetes.