A study published in the Jan. 26 issue of Archives of Internal Medicine found that 90 minutes a week of simple aerobic exercise (such as walking) and 60 minutes of resistance training led to healthy improvements in people 65 and older. "Excess weight, especially around the waist, can cause insulin resistance," says Andrea Dunn, RD, LD, CDE, of the Section of Nutrition Therapy at Cleveland Clinic. "Losing weight, sometimes as little as five to 10 percent, can help." Insulin resistance is a condition in which the body produces insulin but does not use it properly. Insulin, a hormone made by the pancreas, helps the body use glucose for energy. When people are insulin resistant, their muscle, fat, and liver cells do not respond properly to insulin. As a result, their bodies need more insulin to help glucose enter cells. The pancreas tries to keep up with this increased demand for insulin by producing more. Eventually, the pancreas fails to keep up with the bodys need for insulin.