Breastfeeding and Weight Loss

As a trainer for women postpartum, the #1 concern I hear from almost all my clients usually has to do with breastfeeding. An understandable and completely valid concern! It’s true that you must eat extra to sustain breastfeeding, but studies have shown that some calorie restriction can help weight loss without affecting infant growth.

If you read my other article here on breastfeeding and exercise you will discover that exercise usually does not affect milk supply and composition, but what about diet? Is it okay to diet while breastfeeding? **Please note…when I refer to ‘diet’ I simply mean paying attention to what you eat so that you may eat healthy and stay without a suitable calorie goal, no crash diets or crazy restrictions!

breastfeeding and weight loss

A study published in the New England Journal of Medicine looked at the effects of adding diet to exercise in overweight, lactating women and the effect it has on weight loss and the growth of their infants (2000). A group of sedentary women were randomly sorted at four weeks postpartum to either an exercise + diet group or control group. The exercise + diet group was told to restrict their calories by 500 calories/day and engage in an exercise protocol that consisted of 4 days a week of aerobic exercise. (Calories required was determined based on weight, height, age and activity level and the estimated 500 calories required for breastfeeding was added). Nobody was prescribed a diet of fewer than 1793 calories. The control group was told to remain sedentary and not make any changes to their diet.

After ten weeks, the study found that the exercise group lost on average ~10.5 pounds compared to ~1.8 in the control group. It also found that gain in infant weight and length was similar in both groups (Lovelady et al.,2000).

breastfeeding and weight lossOverall, the research suggests that exclusively breastfeeding for at least six months promotes postpartum weight loss. But some women may need to add diet and exercise to get back to their pre—pregnancy weight. Not only does it promote weight loss but exercise also helps increase strength, endurance, and aerobic capacity. It also improves cholesterol and insulin response (Lovelady et al., 2009).

It’s important to note that breastfeeding alone seems only to help women lose weight in those who have a BMI of less than 35. Once lactation is established, overweight and obese women may safely restrict their calories by 500 calories/day to promote a weight loss of 1 pound/week, which has not shown to affect infant growth.

So what should you do? If you are exercising and breastfeeding it IS important to eat enough calories to sustain the extra calories burned during exercise, but there is no need to go overboard! Also, be sure to fill your day with healthy, protein and nutrient rich foods that will help both you and your baby!

Did you also know that breastfeeding promotes decreased weight gain long term? A study by Rooney and Schauberger found that women who breastfed for at least 12 weeks had the smallest weight gain at a ten year follow up. So not only will it help you and baby now, but also helps you maintain your health goals years down the road!

breastfeeding and weight loss


Lovelady, CA. (2011). Balancing exercise and food intake with lactation to promote post-partum weight loss. Proc Nutri Soc May 70(2):181-4.

Lovelady CA, Garner KE, Moreno KL, et al.(2000) The effect of weight loss in overweight, lactating women on the growth of their infants.N Eng J Med 342, 449–453

Lovelady CA, Bopp MJ, Colleran HL et al. (2009) Effect of exercise training on loss of bone mineral density during lactation. Med Sci Sports Exer 41, 1902–1907

Rooney BL & Schauberger CW (2002) Excess pregnancy weight gain and long-term obesity: One decade later.Obstet Gynecol 100, 245–252





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