Researchers at the University of Barcelona found that the traditional Mediterranean diet topped a low-fat diet in helping older adults improve their cholesterol, blood pressure and blood sugar levels. Mediterranean-style eating generally means plenty of fruits, vegetables and whole grains, limited amounts of red meat and processed foods, and a relatively high amount of fat from olive oil and nuts. Experts believe the benefit stems from the fact that the unsaturated fats found in olive oil and nuts actually help protect the cardiovascular system.
The researchers repeated their findings in another study of 7447 men and women aged 55-80, which ran from 2003 to 2010. The participants were randomly assigned to one of three diets: an unrestricted-calorie Mediterranean diet rich in olive oil, an unrestricted-calorie Mediterranean diet rich in nuts, or a low-fat diet where the advice was to avoid all dietary fat.
After 5 years, total fat intake in the low-fat diet group decreased from 40% to 37.4%, and slightly increased in both Mediterranean diet groups (40% to 41.8% in the olive oil group; 40.4% to 42.2% in the nut group).
On average, participants in all three groups lost some weight, but the olive oil group lost the most. They saw a 0.88 kg weight reduction compared to a 0.60 kg weight reduction in the low-fat diet group. But the nuts group saw the lowest weight reduction at 0.40 kg, which does counter part of their prior hypothesis.
But the researchers still hold strong that fat limitations are not beneficial to long-term health and should be reevaluated.