The Mediterranean diet, rich in vegetables, legumes, fish, and “good” fats, has a well-earned reputation for its potential health benefits—including a lower risk of type 2 diabetes. In fact, the diet is strongly recommended by the American Diabetes Association as one way to help prevent (or manage) the disease. Now a new study shows that you can get even more from the diet by watching calories and moving more. 

The study, published in the Annals of Internal Medicine in August, found that older adults at heightened risk of type 2 diabetes were able to lower those odds by one-third more if they combined a traditional Mediterranean diet with calorie reduction and daily physical activity, compared with following the diet alone.

The results build on previous research showing that simply eating Mediterranean-style—without any calorie limits or exercise plan—lowered older adults’ diabetes risk, versus following a low-fat diet.

Study setup, key conclusions

The findings come from a clinical trial that involved over 4,700 adults ages 55 to 75 who were overweight or obese and had metabolic syndrome—a collection of risk factors for type 2 diabetes that includes chronically elevated blood sugar levels, high blood pressure, high triglycerides, and large waist size (40 inches or more for men, 35 inches and up for women).

Researchers randomly assigned each participant to one of two groups: an “intervention” group that followed a reduced-calorie Mediterranean diet and gradually increased their daily physical activity; or a comparison group that also ate Mediterranean-style, but with no calorie-counting or exercise goals. Those in the intervention group aimed to trim 600 calories from their usual daily intake.

Both groups got some help in making diet changes. They periodically met with a dietitian—with the intervention group having more frequent meetings—and they received a free bottle of olive oil (a Mediterranean diet staple) every month.

As for exercise, the intervention group was encouraged to increase aerobic activity—mainly brisk walking—to 45 minutes six days a week, and to do strength training and exercises for flexibility and balance two to three times a week.

Those efforts paid off. Over six years, 9.5 percent of participants in the intervention group developed type 2 diabetes, versus 12 percent in the comparison group. That amounted to a 31 percent reduction in diabetes risk, relative to Mediterranean-style eating alone.

The power of diet + exercise

Over the years, many studies have linked traditional Mediterranean-style eating to lower risks of various major diseases. Along with type 2 diabetes, they include heart disease, stroke, certain cancers, and Alzheimer’s disease.

Researchers believe that the Mediterranean eating pattern has some key health benefits due to its nutritional content. It emphasizes vegetables, whole grains, fish, legumes, healthy unsaturated fats from olive oil and nuts, and moderate amounts of dairy products—while also limiting added sugars and red and processed meats. According to prior research, all of those elements combined may help regulate blood sugar, reduce chronic inflammation in the body, and create a healthier balance of gut bacteria.

The authors of the new study suspect that the intervention group benefited from the Mediterranean diet itself, as well as physical activity—which can also help lower blood sugar levels and reduce inflammation. In addition, people in that group typically shed some pounds and belly fat, which can help ward off type 2 diabetes. On average, they lost a little over 7 pounds and 1.5 inches from their waistlines—whereas people in the comparison group showed no changes overall.

Sustainable success

If all of the above sounds like a lot of change, this study suggests it is doable. In general, people in the intervention group not only revamped their diets and got moving, but also stuck with those habits over the six-year follow-up. And based on periodic questionnaires, both groups maintained their adherence to the Mediterranean diet over time, rather than falling back into their old ways of eating.

As the researchers point out, that might be because Mediterranean-style dining is, quite simply, enjoyable. It’s not overly restrictive—with around 35 to 40 percent of calories from fat, and 40 to 45 percent from carbs—which may make it sustainable for many people.

Type 2 diabetes affects about 38 million Americans, including 30 percent of those ages 65 and older. Considering the disease is a prime risk factor for heart disease, stroke, and kidney disease, anything you can do to prevent or delay its onset could have a major payoff. And as this trial (where the average age was 65 at the start) reminds us, it’s never too late to make lifestyle changes for the better.