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Researchers say what you eat is more important than body mass index (BMI) in terms of cardiovascular disease risk. Getty Images
  • Researchers report that a healthy, Mediterranean-style diet is more important for heart health than weight loss.
  • They say that being thinner isn’t necessarily healthier, especially if the weight loss has occurred from extreme dieting or other methods that reduce nutrition value.
  • They do note that a healthy diet can lower the risks associated with obesity, but it doesn’t eliminate those risks.

If you are overweight, you don’t necessarily have to lose weight in order to live longer.

But you probably need to change your diet.

Research has shown that people with high body mass index (BMI) are at significantly higher risk of all-cause mortality than those who have lower BMI.

High BMI accounts for more than 4 million deaths annually, with more than two-thirds of those deaths due to cardiovascular disease.

This data is considered crucial since 42 percent of people in the United States are clinically obese, according to the Centers for Disease Control and Prevention (CDC).

However, a new study led by Dr. Karl Michaëlsson, a researcher at Uppsala University in Sweden, concludes that people classified as obese can reduce mortality risk to the same level as people with lower BMI by switching to a healthier, Mediterranean-style diet.

The Mediterranean diet favors nutrient-dense foods such as fruits and vegetables, legumes, nuts, unrefined or high-fiber grains, fish, and olive oil over red meat and processed foods.

The study, published in the journal PLOS Medicine, tracked 79,003 Swedish adults with a mean baseline age of 61 for 21 years. During the study period, 30,389 people died.

Researchers found that overweight individuals who best complied with a Mediterranean diet were the least likely to die.

In fact, obese individuals with the healthiest diets were no more likely to die than those people with moderate weight and healthy diets.

Individuals with a “normal” BMI but unhealthy diets also had a higher mortality rate than those with moderate weight who had healthier, Mediterranean-style diets.

Diet was found to be such a strong predictor of mortality risk that the older people in the study who had moderate weight but an unhealthy diet were reported by researchers as the most likely to die during the study period — even more than people with obesity who ate poorly.

“My view is that it is advisable not to make recommendations based on a single study, even if it is my own, but our results indicate that eating healthy is beneficial independent of the relative body weight, at least in later years of life,” Michaëlsson told Healthline.

While cardiovascular mortality associated with high BMI was reduced by adherence to a Mediterranean diet, it was not eliminated, researchers said.

Moreover, lower BMI did not counter the elevated cardiovascular mortality associated with an unhealthier diet.

“These results indicate that adherence to healthy diets such as a Mediterranean-like diet may be a more appropriate focus than avoidance of obesity for the prevention of overall mortality,” the study concluded. “Nonetheless, a healthy diet may not completely counter higher [cardiovascular] mortality related with obesity.”

Dr. Dexter Shurney, the chief medical officer and president of the American College of Lifestyle Medicine, told Healthline that the study findings square with the experience of treating people with type 2 diabetes, who can reverse their condition by adopting a healthier diet even without losing weight.

The same has been shown to be true of people with obesity who have received bariatric surgery, he said.

“Even if you are not reaching your weight loss goals, following a healthy diet provides numerous other invaluable benefits to your entire body,” Bansari Acharya, a registered dietitian and nutritionist at, told Healthline. “A healthy diet consists of a diet that is rich in fruits and vegetables, nuts, adequate water, legumes, lentils, omega-3 fatty acids, lean protein, and low in saturated fats, trans fats, and processed foods.”

“Especially for cardiovascular health, the components in fruits and vegetables, most importantly, fiber and B vitamins, aid in healthy arteries by helping to ease cholesterol,” she added. “Additionally, obtaining an adequate amount of omega-3 fatty acids, which is found in walnuts, flaxseeds, chia seeds, and fatty fish, is crucial for cardiovascular health.”

Shurney said that people who switch to a Mediterranean-style diet almost inevitably will lose weight.

“If you eat more calorie-dense foods” — whole potatoes rather than potato chips, for example — the weight loss will almost take care of itself,” he said. “You can actually eat more and weigh less.”

Even if you don’t shed the pounds, “At the end of the day, the amount of weight you lose should not be the only indicator of how healthy your body is at a cellular level,” said Acharya.

“You could be losing weight through unhealthy means such as by severely restricting your calories, which may deplete you from essential nutrients, further harming your cardiovascular health even while losing weight,” she said. “However, when you incorporate healthy, nutritious, and wholesome foods in your diet, at a cellular level they are helping you regenerate healthy cells and fight off or prevent damage to existing cells.”