By Kelly Bonyata, IBCLC

Yes! Nursing mothers can lose weight safely if they follow some basic guidelines.

Six guidelines for safe dieting during lactation

Wait until your baby is two months old before dieting

It’s best not to do anything consciously to lose weight until after the second month. This gives your body enough time to successfully establish a healthy milk supply that is less likely to be adversely affected if your caloric intake is restricted. Breastfeeding your baby, on average, burns 200-500 calories per day (above what you needed to maintain your pre-pregnancy weight) — so keep in mind that even without a weight loss program you are burning extra calories.

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Breastfeed without restriction

Research tells us that both more frequent breastfeeding and breastfeeding longer than six months increases maternal weight loss.

Eat at least 1500-1800 calories per day

While nursing, you should not consume less than 1500-1800 calories per day, and most women should stay at the high end of this range. Some mothers will require much more than this, but studies show that going below this number may put supply at risk.

Keep weight loss at less than 1.5 pounds per week

Most moms can safely lose up to 1.5 pounds per week or 6 pounds per month after the second month and not affect milk supply or baby’s well being. One study has suggested that short-term weight loss of 2.2 pounds (1 kg) per week is not a problem (in this study, moms dieted for 11 days).

Decrease the calories gradually

A sudden drop in calories can reduce milk supply. Some moms notice this during an illness, although dehydration and/or medication use could also be a factor in reduced milk supply when mom is sick. It has been hypothesized that a sudden calorie decrease can cause mom’s body to go into “starvation mode” and cut nonessential resources such as milk production.

Avoid quick-fix solutions

Liquid diets, low-carb diets, fad diets, weight loss medication, etc. are not recommended while breastfeeding.

What might happen if a nursing mother loses weight too quickly?

In most instances of too-rapid weight loss, it is not the breastmilk (composition or supply) that would suffer, but mom’s nutrition and/or health.

Excessive dieting can result in a reduced milk supply.

According to Breastfeeding and Human Lactation (3rd Edition, Riordan, pp 440), it is noted that fad or rapid weight loss programs should be avoided because fat-soluble environmental contaminants and toxins stored in body fat are released into the milk when caloric intake is severely restricted. I was unable to find a definition of “severely restricted” but I expect that it is significantly under 1500 calories per day (which they called a “modest intake”). I’ve included information on a study on this subject below. See also the info at this website regarding environmental contaminants and breastfeeding.

Three great tips for weight loss (whether you are nursing or not)

Make dietary changes — decrease your fat intake to 20-25% or less of total calories; keep your protein intake up to prevent loss of muscle mass (Recommended Intake of protein for nursing mothers is 65 grams/day for the first 6 months and 62 grams/day between 6 and 12 months).

Spread your calorie intake out — instead of 2-3 meals, eat 3 smaller meals with snacks between. Your body will be less likely to go into “starvation mode” if you are eating small amounts throughout the day.

Exercise moderately so that you burn more fat while keeping lean muscle mass. Resistance/weight training is a good way to build muscle mass. A person with more muscle mass burns more calories, even when resting.

Specific weight loss methods

Weight Watchers, Body for Life

Weight Watchers and Body for Life are generally considered to be fine for breastfeeding mothers. Weight Watchers has a program specifically aimed at nursing mothers. As always, avoid cutting calories too abruptly or losing weight too quickly.

South Beach Diet, Atkins Diet

See Low carb diets and breastfeeding.

Herbal weight loss products

See Herbal weight loss products and breastfeeding.

Additional information

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@ other websites

Nutrition Analysis Tool (NAT) from the Food Science and Human Nutrition Department at the University of Illinois

Hammer RL and Hinterman C. Exercise and Dietary Programming to Promote Maternal Health Fitness and Weight Management During Lactation. Journal of Perinatal Education, 7(2), 13–26.

Books

Eat Well,

Lose Weight

While Breastfeeding

by Eileen Behan, RD

Research

Lovelady CA, et al. Weight change during lactation does not alter the concentrations of chlorinated organic contaminants in breast milk of women with low exposure. J Hum Lact 1999 Dec;15(4):307-15. The results of this study suggest that moderate weight loss (4.1 kg/9 lbs between 4 and 20 weeks postpartum) in lactating women with low exposure to environmental contaminants does not increase contaminant concentration in breast milk.

McCrory MA. Does dieting during lactation put infant growth at risk? Nutr Rev 2001 Jan;59(1 Pt 1):18-21. For some women, postpartum retention of weight gained during pregnancy may contribute to obesity. A recent 10-week randomized intervention showed that infants of initially overweight, lactating mothers who exercised and dieted to lose an average of 0.5 kg/week grew normally.

Lovelady CA, et al. The effect of weight loss in overweight, lactating women on the growth of their infants. N Engl J Med 2000 Feb 17;342(7):449-53. This study found that weight loss of approximately 0.5 kg (1.1 pound) per week between 4 and 14 weeks post partum in overweight women who are exclusively breast-feeding does not affect the growth of their infants.

McCrory MA, et al. Randomized trial of the short-term effects of dieting compared with dieting plus aerobic exercise on lactation performance (link is to full article). Am J Clin Nutr 1999 May;69(5):959-67. This study found that short-term weight loss (approximately 1 kg/2.2 pounds per week) through a combination of dieting and aerobic exercise appears safe for breast-feeding mothers and is preferable to weight loss achieved primarily by dieting because the latter reduces maternal lean body mass. Longer-term studies are needed to confirm these findings.

Dewey KG. Effects of maternal caloric restriction and exercise during lactation (link is to full article). J Nutr 1998 Feb;128(2 Suppl):386S-389S. Studies suggest that, for women who are not underweight initially, lactation is not adversely affected by moderate rates of weight loss (no more than 2 kg/4.4 pounds per month) achieved by either caloric restriction or exercise. A short period of more rapid weight loss is not harmful to lactation. It is unknown, however, whether there are risks associated with longer periods of rapid weight loss.

Journal search on dieting and exercise during lactation