Can exercise and diet cure diabetes?

Q. I read about a study at UCLA in which men with type 2 diabetes were in a program combining aerobic exercise, low-fat diets, and relatively high amounts of “good” carbohydrates. Half of them cured their diabetes. Is this possible?

A. The study you refer to is very small — just 13 men — so it’s far from definitive. Still, the results are intriguing and worth following up. After three weeks of a pretty strict exercise and diet program, nearly half of the participants managed to lower their blood sugar levels so much that they no longer met criteria for diabetes. They exercised 45 to 60 minutes each day and, as you mentioned, it was aerobic exercise, the kind of activity that increases your heartbeat and breathing rate. They were allowed to eat as much as they wanted, but had to avoid fat and “bad carbs” — refined carbohydrates that are easily digested, like those found in soft drinks, pastries, chips, white rice, white breads, and French fries. Sources of “good” carbs include fruits and vegetables, whole-grain breads and cereals, brown rice, and beans.

People with diabetes, as well as those with the high blood sugar levels that often presage the disease, are at increased risk for heart disease and stroke. The UCLA researchers found that in addition to lowering blood sugar levels, the diet and exercise program reduced the inflammation and oxidative stress that leads to atherosclerosis, the main cause of heart disease and stroke.

The UCLA program didn’t “cure” diabetes: It lowered blood sugar levels during the three weeks that people were on the exercise and diet program. Diabetes is a disease that lasts a lifetime, and it requires treatment for a lifetime. For some people, changes in exercise and diet can keep the blood sugar levels normal — so long as they are continued.

Many studies have shown that lifestyle changes can not only help people manage diabetes but also provide powerful protection against ever getting the disease. In 2007, the British Medical Journal published a review of 17 diabetes prevention studies that included a total of about 8,000 people with high blood sugar levels but not full-fledged diabetes. The reviewers concluded that a combination of diet and exercise — without any medications — can cut the risk of getting diabetes in half.

Particularly if you’re overweight, but even if you’re not, you can do more to protect yourself against getting diabetes (and the atherosclerosis that often accompanies it) with lifestyle changes than with any medicine, all without the risk of the side effects that medicines can cause.

—    Anthony L. Komaroff, M.D.
Editor in Chief, Harvard Health Letter

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