Effects of Diet and Exercise on Insulin Resistance during Pregnancy.

Current evidence suggests that both diet and exercise can alter the usual increase in insulin resistance seen in Western societies during mid and late pregnancy. A low-glycemic diet combined with a low-volume exercise regimen during pregnancy decreases the glucose and insulin response to both mixed caloric intake and exercise, and probably lowers both 24-h blood glucose concentrations and the maternal substrate utilization ratio of carbohydrate/fat. The end result is a marked decrease in both maternal weight gain and size at birth. Regular weight-bearing exercise alone lowers markers of insulin resistance and lowers blood glucose concentration during and immediately after exercise during pregnancy. Changes in diet and/or physical activity appear to prevent the onset of gestational diabetes mellitus in at-risk women and may be of value in the treatment of those who develop gestational diabetes.