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There is no ultimate diet, but if there were, the Mediterranean plan would come darn close.

Featuring staples like olive oil, nuts and vegetables, the Mediterranean diet has been heralded as a game changer for health and longevity. Countless studies have connected the eating plan to lower risks of heart attack and stroke and some have suggested the diet can even slow or prevent memory loss. Researchers speculate that the protective benefits likely stem from the combined effect of the diet’s healthy fats and nutrients.

Now a new study shows that the Mediterranean diet alone may be enough to reduce the risk of diabetes, without the need to lose weight or exercise.

The research, published in the journal Annals of Internal Medicine, involved more than 3,500 elderly adults who were at high risk for heart disease but did not yet have diabetes. The participants were split into three groups. The first ate a Mediterranean diet high in fruits, vegetables, whole grains and fish, and low in red or processed meat, butter and sweets, supplemented with extra-virgin olive oil. The second group had a Mediterranean diet supplemented with nuts, and the final group, the control group, consumed a low-fat diet. All the participants were told that they did not have to restrict calories or increase their physical activity.

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After four years, the researchers found that the individuals who developed diabetes were most likely to be in the control group. Of all the participants, 273 developed diabetes; 101 were in the control group. Among those eating the Mediterranean diet, 80 participants in the olive-oil group developed diabetes and 92 in the nut group did. Interestingly, there were no differences in weight loss among the groups; in fact, changes in body weight and amount of physical activity were minor overall.

What’s so beneficial about the Mediterranean diet? The vegetables, seeds and fish contain many minerals and phytochemicals that scientists believe can fight inflammation and insulin resistance, or the body’s gradual inability to break down sugars with insulin that can be a precursor to Type 2 diabetes. The findings are exciting because they imply that these factors alone, and not weight loss, which is another contributor to insulin resistance, can stave off diabetes. Plus, the researchers say, the participants found the Mediterranean diet easier to follow than the low-fat plan. It’s not a guarantee for a free pass from diabetes, but it does hint that diet can play a powerful role in people’s risk for disease. “This dietary pattern is palatable and has a high potential for long-term sustainability, with obvious public health implications for primary prevention of diabetes,” the authors write.

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