Type 2 Diabetes Prevention

Diet and exercise are the cornerstones for preventing type 2 diabetes. These measures are especially important for people with risk factors for the disease, such as prediabetes, obesity, a family history of diabetes, diabetes during pregnancy (gestational diabetes), or an ethnic background (black, Hispanic, Asian, or Native American) that puts them at higher risk. Quitting smoking may be helpful, too.

Diet and exercise

Research studies from around the globe all show that modest weight loss and regular physical activity can help to prevent type 2 diabetes. The largest and best known of these studies is the Diabetes Prevention Program, which was done in the United States.

Study participants who followed a low-calorie, low-fat diet, exercised 30 minutes a day, and lost an average of 15 lbs were almost 60 percent less likely to develop type 2 diabetes over a three-year period than people who did not make these lifestyle changes.

A high-fiber diet also may decrease the risk of developing type 2 diabetes. In a study of nearly 36,000 women, those who consumed the most fiber from cereal had a 36 percent lower risk of developing type 2 diabetes than those consuming the least fiber from cereal. A more recent study from Finland reported similar results in men. Fiber, commonly found in whole grains such as brown rice or wheat bread, may improve the body's sensitivity to insulin.

A Harvard study, involving 84,000 female nurses, found that women who supplemented their diets with at least 1,200 mg of calcium and 800 IU of vitamin D lowered their risk of type 2 diabetes by a third.

Quit smoking

Quitting smoking may reduce the risk of type 2 diabetes, too. A study of more than 21,000 U.S. male physicians found that those who smoked 20 or more cigarettes a day were 70 percent more likely to develop diabetes than those who had never smoked or were former smokers.


Several studies show that oral medications used to treat type 2 diabetes can also help prevent the disease. For example, participants in the Diabetes Prevention Program who took the diabetes drug metformin (Glucophage) reduced their risk of type 2 diabetes by about 30 percent over a three-year period, compared with people who received a placebo. Metformin was as effective as lifestyle measures for only a small percentage of people: those ages 24–44 and those who were obese (50–80 lbs overweight). The drug was just slightly effective in people age 60 and older and in those who were less overweight.

Based on these findings, the American Diabetes Association does not recommend the use of oral diabetes drugs as a substitute for, or in addition to, lifestyle modifications like diet and exercise to prevent diabetes.

In another study, the Heart Outcomes Prevention Evaluation (HOPE), people taking the ACE inhibitor ramipril (Altace) were 30 percent less likely to develop diabetes than those taking a placebo. However, more research is needed before ACE inhibitors can be recommended for preventing diabetes.

Publication Review By: Written by: Christopher D. Saudek, M.D.; Simeon Margolis, M.D., Ph.D.

Published: 20 Apr 2009

Last Modified: 08 Oct 2015