A study has delivered the news we've been waiting our whole lives to hear: a high-fat diet doesn't cause weight gain — just as long as those fats are the kind you find in the Mediterranean diet, and especially in olive oil. This isn't the first study to claim that the Mediterranean diet is the best for those looking to lose weight. Both studies challenge the widely held perception that eating fat is harmful.
The study, conducted by Predimed, surveyed over 7,000 men from 55 to 80 and monitored them over a five-year period. Their diets did not include red meat, butter, or sugar, and instead placed an emphasis on fish, nuts, vegetables, and fruit.
At random, the researchers assigned the participants three variations of a Mediterranean diet: an unrestricted calorie regimen with added extra-virgin olive oil, an unrestricted calorie regimen with added nuts, and a low-fat diet. After five years, those who ate the diet with olive oil saw the highest average weight loss. Since waist size tends to increase with age, it's normal that the average size increased with time — but the group who saw the lowest increase in waist size was also the diet with olive oil.
The study is an important step toward demonstrating that not all fats are bad. As the team shared with the Guardian:
"The fat content of foods and diets is simply not a useful metric to judge long-term harms or benefits. Energy density and total caloric contents can be similarly misleading. Rather, modern scientific evidence supports an emphasis on eating more calories from fruits, nuts, vegetables, beans, fish, yogurt, phenolic-rich vegetable oils, and minimally processed whole grains; and fewer calories from highly processed foods rich in starch, sugar, salt, or trans-fat."
Obviously, this does not mean we can gorge on fats and expect to lose weight, but it does mean you can stop vilifying fats as harmful to your health.