The effects of a low-glycemic index diet on pregnancy rates in overweight women with fertility issues

Obesity can cause hormone imbalances that affect fertility. The changes in the body that occur with excess weight can cause problems with egg development, ovarian function, and the endometrium (the lining of the uterus). This reduces the woman’s ability to get pregnant. One of the first treatment goals for women with infertility is to lose weight and balance hormone levels. Low-glycemic index (LGI) diets in particular seem to have a good effect on hormone levels. Whether an LGI diet can affect pregnancy rates in obese infertile women undergoing in vitro fertilization (where an egg is fertilized outside the body and then implanted into the woman’s uterus) is unclear. 

In this study, 14 obese or overweight women were put on a low calorie, LGI diet for 12 weeks. 12 women stayed on their normal diet. The women had dietary advice from a qualified dietician, and they had to keep a food diary. LGI foods were foods with a glycemic index of less than 50 (the glycemic index of foods are rated between 0 and 100. Pure glucose (sugar) is rated 100). After 12 weeks, all participants then underwent in vitro fertilization (IVF) treatment. 

After 12 weeks, the LGI-diet group had a greater reduction in body weight and body fat. There was a 26% reduction in the hormone leptin (which regulates body fat and appetite). The LGI group also produced 85.4% more eggs during IVF. 3 women in the LGI-diet group experienced spontaneous pregnancies, which resulted in three live births. There were no pregnancies in the normal-diet group.

The study concluded that the low-calorie, LGI diet improved weight loss and pregnancy rates in overweight women with infertility. 

This was a very small, short-term study. Further studies including a larger number of women must be done to determine whether these results can be generalized to a larger population.