Effects of a low-glycemic load diet in overweight and obese pregnant women a pilot randomized controlled trial

Background The optimal diet for pregnancy that is complicated by excessive weight is unknown Objective We aimed to examine the effects of a low-glycemic load (low GL) diet in overweight and obese pregnant women Design We randomly assigned 46 overweight or obese pregnant women to receive a low GL or a low fat diet Participants received carbohydrate rich foods fats and snack foods through home delivery or study visits The primary outcome was birth weight z score Other endpoints included infant anthropometric measurements gestational duration maternal weight gain and maternal metabolic parameters Results There were no significant differences in birth weight z score or other measures of infant adiposity between groups How ever in the low GL compared with the low fat group gestational duration was longer (mean +/- SD 39 3 +/- 1 1 compared with 37 9 +/- 3 1 wk P = 0 05) and fewer deliveries occurred at <= 38 0 wk (13% compared with 48% P = 002 with exclusion of planned cesarean deliveries 5% compared with 53% P = 0 002) Adjusted head circumference was greater in the low GL group (35 0 +/- 0 8 corn pared with 34 2 +/- 1 3 cm P = 0 01) Women in the low GL group had smaller increases in triglycerides [median (interquartile range) 49 (19 70) compared with 93 (34 129) mg/dL P = 0 03] and total cholesterol [13 (0 36) compared with 33 (22 56) mg/dL P = 0 04] and a greater decrease in C reactive protein [-2 5 (-5 5 -0 7) compared with -0 4 (-1 4 1 5) mg/dL P = 0 007] Conclusions A low GL diet resulted in longer pregnancy duration greater infant head circumference and improved maternal cardio vascular risk factors Large scale studies are warranted to evaluate whether dietary intervention during pregnancy aimed at lowering GL may be useful in the prevention of prematurity and other id verse maternal and infant outcomes This trial is registered at clinicaltrials gov as NCT00364403 Am J Clin Nutr 2010 92 1306-15