A 2002 Harvard University study found that men who ate three daily servings of whole grains (e.g., brown rice, dark bread, and bran cereal) cut diabetes risk by 42 percent. Whole grains help you keep fat off because they're high in fiber, which leaves you feeling full longer, says study co-author Teresa Fung, Sc.D., R.D. (For shopping tips, see "Whole Grains or Half-Baked?" on page 20.)
High-fiber foods are digested slowly, so they don't cause a spike in blood glucose levels. In contrast, low-fiber carbohydrates like white bread and candy cause glucose levels to soar--and the pancreas responds by flooding the bloodstream with insulin. "You're asking your pancreas to work hard over the years," cautions Fung. "Eventually, you exhaust it." When your pancreas can't keep up with demand, type 2 diabetes is the result.
Compared to non-diabetics, patients with type 2 diabetes tend to have lower levels of this mineral, which your body needs to form enzymes that help burn glucose as energy. A 2004 study, also at Harvard, found that people with the highest intake of magnesium lowered their risk for diabetes by about one-third. Good sources of magnesium include whole grains, nuts, green leafy vegetables, and supplements.
Prediabetics might benefit from adding cherries to their diet, says Muraleedharan G. Nair, Ph.D., a professor in the department of horticulture and the National Food Safety & Toxicology Center at Michigan State University. Nair and his colleagues put rats on a high-fat diet, then fed them anthocyanins, which are compounds that give cherries (and raspberries and elderberries) their striking color. The rats lost 24 percent of their body weight; their blood sugar, which shot up with the high fat intake, returned to normal. The same researchers showed that treating pancreas cells in cultures with anthocyanins and related compounds from fruits makes them produce 50 percent more insulin.