Foods That Prevent Diabetes are Right in your Kitchen

Finding foods that prevent diabetes is easy once you know what to look for.


Finding foods that prevent diabetes is easy once you know what to look for.

An explosion. That’s how experts describe worldwide diabetes rates.

And type 2 diabetes—which used to be called “adult-onset”—is now being diagnosed in adolescents. So why does diabetes belong in the “Diseases We Can Prevent” group? Because we know that the foods we eat and the exercise we get can help lower our risk of being diagnosed with diabetes.

We know that obesity is, by far, the most important cause of diabetes. “Studies suggest that more than 80 percent of diabetes is due to overweight and obesity,” says JoAnn Manson of Harvard Medical School.  “Obesity is more closely linked to diabetes than any other health problem.”

That’s one reason why diabetes is more and more of a problem: worldwide obesity rates are soaring. In the U.S., “the prevalence of obesity has increased 30 percent in the last ten to 15 years,” explains Manson. The incidence of diabetes has also climbed along with that. A woman of average weight in the U.S. has double the risk as a woman of optimal weight.

As a nation, we’re paying the piper for years of “super-size” fries and all-you-can-eat buffets, says Manson.

A sedentary lifestyle also boosts the odds, whether you’re overweight or not. “Physical activity can reduce the risk of diabetes,” says Manson. “Even moderate exercise such as walking is protective.”

Which foods help lower the risk of diabetes?

Whole grains. When researchers pooled data from six studies of more than 286,000 participants, they estimated that for every two servings of whole grains you eat a day, your risk of diabetes drops by 21 percent.

Why? “Whole grains lead to smaller fluctuations in blood sugar and insulin than refined grains and sugars,” says Manson. “Whole grains may also lead to more satiety. Refined carbs can lead to hunger and increased food intake due to the wide swings in blood sugar.”

But, she cautions, “people who eat whole grains tend to exercise more, smoke less, and have a healthier dietary pattern.” And those things could help account for the link.

Magnesium-rich foods like leafy greens and beans. “Magnesium is understudied and under-appreciated for its effect on both glucose tolerance and cardiovascular disease,” says Manson.

In a study that tracked 85,000 women for 18 years and 42,000 men for 12 years, those who consumed the most magnesium (about 375 milligrams a day for women and 450 mg a day for men) from food and supplements combined had a 33 percent lower risk of diabetes than those who consumed the least (220 mg a day for women and 270 mg a day for men). Another study found lower blood insulin levels and a lower risk of diabetes in women who consumed the most magnesium.

“It’s biologically plausible that magnesium would have an effect on glucose tolerance and insulin sensitivity,” notes Manson.

Small studies have already tested magnesium supplements on people who have diabetes. And magnesium supplements (365 mg a day) have lowered insulin resistance and fasting blood sugar levels in overweight people who don’t have diabetes.

“Larger trials are needed,” says Manson. In the meantime, it makes sense to eat magnesium-rich foods rather than take a supplement. Taking high doses (more than 350 mg) of magnesium leads to mild diarrhea or other gastrointestinal complaints in some people.

Nuts. When researchers at Harvard University tracked the eating habits and health of about 84,000 nurses for 16 years, they found that those women who consumed nuts five or more times a week had about a 25 percent lower risk of developing diabetes than women who seldom if ever ate nuts. And women who ate peanut butter five or more times a week had a 20 percent lower risk of diabetes then women who didn’t eat peanut butter.

It’s not clear whether nuts lower the risk of diabetes because they’re high in magnesium, unsaturated fats, or fiber or whether something else about nut eaters lowers their risk. The researchers took into account the fact that the nut eaters ate healthier diets, were less likely to smoke and be overweight, and were more likely to exercise. But they may have missed something else about nut eaters that made them healthier.

Just keep in mind that nuts are calorie-dense, so you can’t add them to your diet without removing something else, like refined grains and red meat. You’ll get 150 to 185 calories in a one-ounce serving of dry-roasted nuts. That’s just 22 almonds, three tablespoons of cashews, 28 peanuts, 47 pistachios, or 14 walnut halves.

Coffee. When researchers examined nine studies on more than 193,000 people, they found that those who drank four to six cups of regular coffee a day had a 28 percent lower risk of diabetes than those who drank no more than two cups a day.

“Decaf is also associated with a lower risk of diabetes, so something other than the caffeine in coffee beans appears to be responsible,” says Manson. “The mechanism isn’t known.”

How else to lower your risk of diabetes

The best way to dodge diabetes is to lose (or not gain) extra pounds.

Limit sweets, especially sugar-sweetened drinks. Even the naturally occurring sugars in 100% fruit juice may raise your risk.

Get the RDA for vitamin D (600 IU a day up to age 70 and 800 IU over 70) from supplements or foods fortified with vitamin D.

Do at least 30 minutes of brisk walking or other aerobic exercise every day. Shoot for 2 or 3 strength-training sessions a week. Each should include 8 to 12 repetitions of 8 to 10 exercises.

Diet and exercise can also help those on the verge of developing diabetes.

Researchers monitored 3,000 overweight people with pre-diabetes—that is, their blood sugar levels were above normal, but not high enough to be diabetes. All were participants in the Diabetes Prevention Program, which randomly assigned more than 3,200 people to an intensive lifestyle intervention, the diabetes drug metformin, or a placebo. The lifestyle intervention included a goal of 150 minutes of exercise a week and diet counseling.

People in the lifestyle group who lost at least 10 percent of their body weight within six months of being diagnosed with pre-diabetes had an 85 percent lower risk of being diagnosed with diabetes over the next three years than those who lost no weight. Those who lost 7 to 9 percent of their body weight lowered their risk by 66 percent, and those who lost 5 to 6 percent of their body weight lowered their risk by 54 percent.

If you’ve been told that you have pre-diabetes, try to lose weight and boost your exercise before your next doctor’s appointment. The Diabetes Prevention Program is now offered at many YMCAs.

Sources:  Ann. Intern. Med. 122: 481, 1995. Lancet 338: 774, 1991. J. Amer. Med. Assoc. 277: 472, 1997. J. Gen. Intern. Med. 2013. doi:10.1007/s11606-013-2548-4. J. Amer. Med. Assoc. 288: 2554, 2002. JAMA 288: 2554, 2002.