Eating just a small handful of pecans a day may protect overweight and obese adults against developing cardiovascular disease and Type 2 diabetes, according to a study published in Nutrients.

Researchers at the Jean Mayer USDA Human Nutrition Research Center on Aging at Tufts University found that incorporating about one-and-a-half ounces of pecans into a typical American diet significantly improved insulin sensitivity and had a marked effect on markers of cardiometabolic disease in overweight and obese adults with excess belly fat.

While many studies have linked tree nuts, such as pecans, walnuts, and almonds, to a reduced risk of heart disease, this was the first study to look at the effect of pecans on factors specifically related to Type 2 diabetes. Obesity is a risk factor for Type 2 diabetes, and both obesity and diabetes increase the risk for heart disease.

"Pecans are naturally high in monounsaturated and polyunsaturated fats, so replacing a portion of the saturated fat in the diet with these healthier fats can explain some of the cardio-protective effects we observed," said lead researcher, Diane McKay, Ph.D.

"But pecans also contain a number of bioactive plant compounds as well as vitamins and essential minerals that all likely contributed to this benefit," she continued. "What's really interesting is that just one small change — eating a handful of pecans daily — may have a large impact on the health of these at-risk adults."

Researchers studied men and women whose average age was 59 years. In the placebo-controlled study, all participants ate either a control diet or one with pecans substituted for 15 percent of the total calories.  Calorie levels, as well as protein, carbohydrate, and total fat, were the same in both diets.

Eating just a handful of nuts a day can cut your risk of many diseases, according to a study from Imperial College London that examined 20 published studies. Researchers found that 20 grams a day, the equivalent of a handful of nuts or about half an ounce, cuts the risk of coronary heart disease by almost 30 percent.

The news for respiratory disease is even better — nuts cut the risk of dying from respiratory disease in half and lower the risk of diabetes by 40 percent. The same handful of nuts also reduces the risk of premature death by 22 percent and cancer risk by 15 percent.

A 2015 study published in the International Journal of Epidemiology found that an even smaller amount of nuts daily — at least 10 grams (about two teaspoons) — lower the risk of dying from seven major causes of death an average of 23 percent when compared to people who eat nut-free diets.