Breastfeeding & Weight Loss

With the new year right around the corner, we are feeling extra motivated and determined to shed those last few pounds. So what is considered safe while breastfeeding to lose the weight and keep up our milk supply? 



Making milk requires energy from our body and when we breastfeed we're burning around 500-700 calories a day just to keep up with our milk production - whew (1,2)! As a result, exclusively breastfeeding mothers may see loss of about 1-2 pounds (.45 - .9 kg) a month as a result of lactation (3). This amount can vary dramatically as our postpartum weight loss is largely influenced by factors such as pre-pregnancy weight, BMI, race, age, diet, physical activity and breastfeeding duration - so while breastfeeding may be helpful in losing some weight, it won't be the key to weight loss for all of us (6). The effect of breastfeeding on weight loss may also increase with the length of breastfeeding - aka the longer women breastfed, the greater the difference in weight loss when compared with those who did not breastfeed/weaned before three months (6,7). 

This biological mechanism for weight loss helps many mamas lose the pregnancy weight without too much effort (you know, other than making milk from scratch and feeding our babies 24/7) but even with exclusive, on-demand breastfeeding about 15-20% of women can't shake the last 10 pounds of weight (3, 4). This is completely normal and we're big fans of embracing the new, postpartum version of you but some women choose to engage in dieting and exercise routines to help trim down.

So what to do about weight loss? Weight loss should be gradual because it is important to ensure we are consuming enough calories to keep up with how much our body is burning. Rapid weight loss may sound like a positive for many, however it can compromise quantity and quality of milk supply so slow and steady goals should be your focus (3). 


It is recommended to not start a weight loss program until milk supply regulates, around 6-8 weeks postpartum (3).


Around 3-5 days postpartum your milk supply will rapidly increase in volume and many women experience an oversupply for the first few weeks/months while our bodies figure out how many babies we are feeding. It generally takes about 6-8 weeks of on-demand breastfeeding for our body to regulate milk production so that we produce only what we tell our body to make (i.e. demand it and your body will supply it) and as long as we are feeding on-demand and following baby's cues, then our body will make the perfect amount of milk for our baby. So, it is during this calibration period that we don't want to interfere, we want our body to have all the energy and nutrition it needs to fuel the milk making process and give us the energy we need to keep up with motherhood. 


Once your milk supply is established and baby is gaining weight well, a breastfeeding mama should aim to lose no more than 1.1 lbs (.45-.5 kg) week (3). Remember, slow and steady to protect your milk supply.  


While breastfeeding, you should be consuming at least 1800 calories/day (3). For some, this may mean you cannot cut out too much food in your day to make sure you're fueling your bodies to keep up with milk production and to ensure you have enough energy to function. It helps to remember when dieting, that its not necessarily about eating a small number of calories but how you choose to select those calories. Whether dieting or not, breastfeeding women should focus on making healthy food choices to fulfill your caloric needs. Decrease the junk food, avoid drinking your calories (e.g. frappuccino, juice, soda) and make sure you're consuming plenty of fruits and veggies, and healthy snacks.


Atkins, Paleo, Vegetarian, Vegan, etc. Many of these types of diets are safe while breastfeeding as long as you keep up with the minimum 1800 calories and make sure you're getting a variety of vitamins and minerals from your food choices or from a supplement.  


Dieting combined with weight loss can help postpartum women lose the weight faster (8). Exercise is vital in keeping us healthy and happy, whether we are breastfeeding or not! Walking, jogging, biking, pilates - the list goes on of the fun physical activities we can engage in to get our bodies moving, our hearts pumping and as a bonus, lose some weight! Once you get the OK from your physician to begin an exercise program (typically 6-8 weeks after delivery), feel free to enjoy your favorite form of physical fitness. There is no evidence to suggest that exercising has any negative effects on milk supply, infant weight gain, or taste of milk (3, 6, 7). 

Let's Recap.

  • Making milk uses up energy in our body aka it burns 500-700 additional calories a day - score! 
  • Breastfeeding may or may not contribute to our postpartum weight loss depending on things like our pre-pregnancy weight, race, age as well as how we are eating, if we are getting any physical activity and if we are exclusively nursing.
  • Have no fear, if you want to shake off those extra pounds gradual weight loss and exercise is OK when breastfeeding. 
  • You should wait to start a weight loss program / reducing calories until your milk supply is established around 6-8 weeks. Aim to lose no more than 1.1 pounds per week to protect your milk supply. Your doctor should give you the OK to exercise once you've healed around 6 weeks postpartum. 
  • If you notice your supply dipping, pause the dieting and increase your calories. Remember, we need to fuel our bodies to make milk. Try again slowly in a few weeks and cut yourself a break. We think motherhood looks great on you. 


(1)  Institute of Medicine. (2002). Dietary Reference Intakes for Energy, Carbohydrate, Fiber, Fatty Acids, Cholesterol, Protein, Amino Acids (Macronutrients). Washington, DC: National Academies Press.

(2) Food and Agriculture Organization of the United Nations. Human energy requirements. Retrieved from

(3) Lauwers, J. & Swisher, A. (2015). Counseling the Nursing Mother: A Lactation Consultants Guide. Burlington, MA: Jones & Bartlett Learning. 

(4) Neville et al. (2014). The relationship between breastfeeding and postpartum weight change— a systematic review and critical evaluation. Int J Obes (Lond), 38( 4), 577-590.

(5) Zhang et al. (2011). Study on the Effect of Moderate Exercise on Lactic Acid Content in Breast Milk by Indirect CE with Amperometric Detection. Chromatographia, 74(3), 275-280.

(6) Dewey et al. (1994). Effects of dieting and physical activity on pregnancy and lactation. Am J Clin Nutr, 59( Suppl 2), 446s-453s.

(7) Neville et al. (2014). The relationship between breastfeeding and postpartum weight change—a systematic review and critical evaluation. International Journal of Obesity, 38, 577-590. 

(8) Lovelady, C. (2011). Balancing exercise and food intake with lactation to promote post-partum weight loss. Proc Nutr Soc, 70(2), 181-184. doi: 10.1017/S002966511100005X