Maintaining a low-fat diet does not appear to reduce the likelihood of post-menopausal women developing diabetes. Decreased fat intake with weight loss and increased exercise may reduce the risk of diabetes mellitus in persons with impaired glucose tolerance. To assess whether or not a low-fat diet reduces the risk of developing diabetes among generally healthy postmenopausal women, researches from America studied postmenopausal women aged 50 to 79 years. Of 48,835 women , 29,294 were randomly assigned to continue eating their usual diet (the control group), and the remaining 19,541 women were asked to go on to a low-fat diet (20 percent of calories from fat) with increased amounts of fruits, vegetables and whole grains. The diet was not intended to help participants lose weight, and neither the diet group nor the control group was given goals for weight loss or physical activity. Self-reported incident diabetes treated with oral agents or insulin was assessed. During 12 years of follow-up, diabetes developed in 7.1 percent of women on low-fat diet and 7.4 percent of those in the control group, not a significant difference statistically. However, among women on the low-fat diet, a trend toward greater reduction in diabetes risk with greater decreases in total fat intake and weight loss was found. Further analysis showed that most of this effect was attributable to weight loss. Women in the low-fat diet group lost about 2 kilograms more weight over the course of the study than women in the control group. The researchers concluded that weight loss, rather than macronutrient composition of the diet, may be the dominant predictor of reduced risk of diabetes.
Archives of Internal Medicine
July 2008