Participants in the study were sedentary, overweight middle-aged men and women who reduced their weight 6 to 8 percent through calorie restriction, exercise or both. Researchers measured their insulin sensitivity levels, which determines risk of diabetes. “Your blood sugar may be perfectly normal, but if your insulin sensitivity is low, you are on the way to blood sugar issues and, potentially, Type 2 diabetes,” Weiss said.
The researchers measured twice the improvement of insulin sensitivity in the group of participants who both exercised and restricted their diets than in the other two groups. Weiss notes that exercise helps regulate glucose, even if a person isn’t losing weight as a result. The researchers also found that exercised-induced weight loss didn’t regulate glucoregulation more effectively than calorie restriction. “What we found is that calorie restriction, like exercise, may be providing benefits beyond those associated with weight loss alone,” Weiss said.
Weiss said that though it might seem obvious that a combination of diet and exercise would engender the best results, “there are a lot of people who believe that if they maintain a healthy weight, it doesn’t matter what they eat. And others have an appropriate food intake but don’t exercise.”