Overweight women who are breastfeeding and want to lose weight can do so safely by decreasing the amount of sweetened drinks, snack foods, sweets and desserts in their diet and walking briskly for 45 minutes per day, four days per week, a new study indicates.

This approach sheds about a pound a week. It does not affect women’s ability to breastfeed, and it’s not harmful to their infants, study chief Dr. Cheryl A. Lovelady of the department of nutrition at The University of North Carolina at Greensboro told Reuters Health.

The post-childbirth period “may be an ideal time to implement an exercise and diet program,” as many women are anxious to lose weight after the baby arrives, she and her colleagues note in the Journal of the American Dietetic Association. However, the effect of dieting on maternal nutrient intake, which impacts the nutrient content of breast milk and maternal health, “must be determined.”

Lovelady’s team determined dietary changes in a group of women participating in a study looking at the effects on infants of weight loss in overweight lactating mothers.

At 4 weeks after delivery - once breastfeeding was established and mothers had recuperated from delivery - 35 overweight breastfeeding women were randomly assigned to reduce their energy intake by 500 calories per day and to exercise, or to maintain their usual diet for 10 weeks (the control group).

Exercise consisted of brisk walking or jogging or aerobic dancing at 65-80 percent of maximum heart rate. Calorie reduction was achieved, in large part, by decreasing consumption of foods high in fat and simple sugars such as chips, soft drinks, sweets, high-fat meat, and food groups containing starches with fat, the investigators note.

All of the women exclusively breastfed during the study and none of the women complained of reduced milk volume or “fussy” infants, or fatigue as a result of dieting and exercising. The infants of mothers in the diet-and-exercise group grew as well as the infants of mothers in the control group, Lovelady said.

The diet and exercisers lost significantly more weight and body fat over the course of the study than the control group.

The team says the dietary changes “added up to a significant decrease in overall kilocalories consumed, without adversely affecting nutrient intake except for calcium and vitamin D.” Lactating women who diet should increase their intakes of foods high in calcium and vitamin D, Lovelady and colleagues advise.

“Lactating mothers should also continue to consume at least three 8-ounce servings of low-fat dairy products and five servings of fruits and vegetables per day,” Lovelady told Reuters Health.

SOURCE: Journal of the American Dietetic Association, June 2006.