Effect of dietary carbohydrate on the glucose and insulin response to mixed caloric intake and exercise in both nonpregnant and pregnant women.

The objective of this study was to test the hypothesis that a woman's dietary carbohydrate mix modifies the glucose and insulin response to both mixed caloric intake and exercise. Either a prospective randomized or a prospective randomized crossover design was used to examine the effects of two isocaloric, high-carbohydrate diets on the whole-blood glucose and insulin responses to mixed caloric intake and exercise in healthy nonpregnant (n = 14) and pregnant (n = 12) women. The diets differed only in the type of carbohydrate ingested. Those in one had low glycemic indexes and those in the other had high glycemic indexes. In nonpregnant women, the blood glucose response to a meal containing low-glycemic carbohydrate was half that seen with high-glycemic carbohydrate, and the effect of exercise on blood glucose was more pronounced while eating the high-glycemic carbohydrate diet. During pregnancy, women on the low-glycemic carbohydrate diet experienced no significant change in their glycemic response to mixed caloric intake, whereas those who switched to the high-glycemic carbohydrate diet experienced a 190% increase in their response. In conclusion, the type of dietary carbohydrate in a healthy, physically active woman's diet influences both her postprandial blood glucose profile and her blood sugar response to exercise.