Four bites a day and you could cut your risk for diabetes by 24%. Just four bites of something that tastes great! Why this matters so much…

We’ve been losing the fight against diabetes—the prevalence of this deadly disease has increased by more than 175% since 1980. Good news: There’s an easy and economical way to help guard against type 2 diabetes. Just eat a particular type of nut—the walnut.

Here are the details you need to know to get this benefit…

The news comes from a huge Harvard study that looked at data on nearly 138,000 women. Every two years, participants answered detailed questions about their health and lifestyle. Every four years, they completed lengthy questionnaires about their diets, indicating how often they consumed each of more than 130 foods, with answers ranging from “never or less than once per month” to “six or more times per day.” At the start of the study, none of the women had diabetes…by the end of the 10-year follow-up, nearly 6,000 had developed the disease.

The researchers performed a careful analysis that adjusted for age, body mass index, family history of diabetes, smoking, menopausal status and other factors that affect diabetes risk. They also adjusted for consumption of various unhealthful foods (such as sugar-sweetened drinks and processed meats) and healthful foods (whole grains, fish, fruits, vegetables and various types of nuts).

What they found: Women who ate two or more ounces of walnuts per week, on average, had a 24% lower risk for type 2 diabetes…those who ate just one ounce of walnuts per week had a 13% lower risk.

Other types of nuts conferred some benefits, but mainly through weight control, the researchers said. The walnut, however, has a number of properties that make it a winner in the fight against diabetes. For one thing, of all the common tree nuts, walnuts are highest in polyunsaturated fats, containing 47% of these fats by weight—and there is good evidence that polyunsaturated fats have favorable effects on how the body uses insulin. Walnuts also are the richest of all nuts in a particular type of healthful polyunsaturated fat called alpha linolenic acid. What’s more, walnuts are high in fiber and plant protein and have been shown to decrease total cholesterol and LDL “bad” cholesterol. These nuts also are loaded with vitamin E and polyphenols that have antioxidant properties. Bonus: Even though walnuts (like other nuts) are high in calories, they don’t seem to cause weight gain in a balanced diet—perhaps because they are so filling and satisfying.

Do men get similar protection against diabetes from eating walnuts? Research will have to prove it, but odds are good that they would.

Going nuts: The best part is that walnuts aren’t some specialty product you have to go out of your way to buy, and you don’t have to drown yourself in walnuts to get the benefits. Two ounces is only 28 walnut halves per week…that’s just four halves per day.

Walnuts are a great snack to have on the road or at work because they don’t need to be refrigerated (though if you’re going to store them for a while, putting them in the fridge or freezer will keep them fresher longer). While this new study did not look at whether the participants ate their walnuts raw, roasted or otherwise cooked, you can certainly use them in cooking if you like because heat won’t significantly affect their health benefits. To increase your intake, try adding chopped walnuts to cereal, salad, rice or soup…stirring ground walnuts into to a smoothie or yogurt…and spreading walnut butter on celery sticks or apple slices.