Dieters beware! A new study suggests that chronic dieting may cause pregnant women to gain more weight compared with pregnant women who didn’t diet. Researchers from the University of North Carolina found that pregnant women who were not underweight, but had a history of restricting their food intake tended to gain more weight than recommended. Dieters gained more weight than women who were normal, overweight, or obese at the start of their pregnancy. In comparison, underweight women who previously dieted tended to gain less than the recommended amount weight at the start of their pregnancy.

Many experts maintain that during pregnancy women should gain 28 to 40 pounds if they are underweight, 25 to 35 pounds if normal weight, 15 to 25 pounds if overweight and at least 15 pounds if obese.

“During pregnancy it would be useful to target these women with similar nutritional and physical activity strategies in order to avoid excessive weight gain and adverse pregnancy outcomes, such as Caesarean sections, macrosomia [newborns with excessive birth weight] and large-for-gestational age [LGA babies], as well as shorter duration of breast feeding and higher weight retention in the postpartum period,” said Anna Maria Siega-Riz MD, co-author of the study.