Published in the latest issue of the British Medical Journal, the study found that 48% of women who stuck with their usual diets while pregnant gained more weight than recommended. However, only 38% of women who switched to a diet of low glycemic foods gained too much weight.

According to MyHealthNewsDaily, the Institute of Medicine recommends that women of normal weight gain 25 to 35 pounds (around 11-13.5 kilos) during pregnancy.

In the study, the average weight gain among women who remained on their usual diet was 30 pounds (13.7 kilograms). Among women who changed to a low glycemic index diet, weight gain was 27 pounds (12.2 kg).

While it may not seem like much, researchers warn this extra weight can spell trouble for moms-to-be. "This type of excessive weight gain during pregnancy is associated with an increased need for delivery by Caesarean section, a higher likelihood of post pregnancy weight retention, and a higher predisposition to obesity in later life," said researcher Dr. Fionnuala McAuliffe of the UCD School of Medicine and Medical Science, University College Dublin, and the National Maternity Hospital, Dublin. The study involved more than 800 women treated at National Maternity Hospital in Dublin.

Selecting foods lower on the glycemic index means avoiding blood sugar spikes with white rice, sweets, and white flour breads and opting for fresh foods, such as vegetables, meat, and fruits. Whole grains, such as brown bread and brown rice, also have lower glycemic indexes than white bread and white rice.