Breastfeeding, Weight Loss

Don't Count on Breastfeeding to Help You Shed Your Baby Weight

Like so many new moms, I was told ad nauseam that breastfeeding melts off baby weight. And not just by random strangers. The American Academy of Pediatrics (AAP). states that breastfeeding leads to an “earlier return to prepregnancy weight”.

Breastfeeding supposedly helps you lose weight, because, as many popular websites, like WebMd claim, “breastfeeding burns extra calories, so it can help you lose pregnancy weight faster.”

Sounds pretty convincing, right?

So when I failed to lose weight while breastfeeding my first child, I was shocked. Weren’t those pregnancy pounds supposed to practically fall off? Why were my pre-pregnancy jeans still relegated to the back of my closet?

By exclusively breastfeeding, I was burning an average of 480 calories a day, but the pregnancy pounds were still clinging to my waist and hips.

So, naturally, I turned to the research, and learned that, like so many other widely alleged benefits of breastfeeding, breastfeeding-aided weight loss is vastly overblown.

My experience was not weird, but completely normal. For most well-nourished women, long-term breastfeeding results in only a trivial amount of extra weight loss by 6 months postpartum, of around 1-2 lbs.

“In most reports, rates of weight loss did not differ between lactating and nonlactating women.” states a 1998 review of the research on postpartum weight loss.

“The effect of breastfeeding in mothers on return-to-pre-pregnancy weight was negligible, and the effect of breastfeeding on postpartum weight loss was unclear,” concludes another large 2007 review.

Large research reviews all find that breastfeeding does lead to greater weight loss at 6 months after birth, but that the amount lost is so tiny as to be trivial: Breastfeeding mothers shed an extra 1-2 lbs on average–provided they breastfed for at least 6 months. Breastfeeding during the first 3 months after giving birth has no effect on weight.

(According to a 2015 review, randomized controlled trials put the added weight loss for breastfeeding mothers at an average of about 1 lb. Cohort studies report a greater amount, of about 2.5 lbs. The true benefit is thus probably closer to an average of 1 lb than of 2.5 lbs.)

In short, while there may be lots of good reasons to breastfeed, weight loss does not seem to be one of them.

Why Doesn’t Breastfeeding Lead to Greater Weight Loss?

Breastfeeding sure seems like it ought to lead to significant weight loss. Breastfeeding, after all, does require calories. Lots of them. Women burn between 400-560 extra calories a day breastfeeding during the first 6 months after giving birth, the amount burned by an hour of running.

So why aren’t breastfeeding women shedding their baby weight?

Unfortunately, when it comes to taking off those extra pregnancy pounds, your biology is working against you.

In food-rich environments, breastfeeding women make up for the extra calories burned breastfeeding not from fat reserves, but by eating more and moving less.

Breastfeeding makes you hungry. Prolactin, the major hormone regulating breast milk production, is released each time you nurse; it is a potent stimulator of appetite.

Prolactin may explain why breastfeeding frequency is inversely related to weight loss–the more often women breastfeed, the less weight they tend to lose.

During the first 3 months of breastfeeding, when feedings are most frequent, breastfeeding moms lose weight at the same rate as formula-feeding moms. But between 3 to 6 months, when milk production remains high but feedings are spaced further out, breastfeeding moms lose a little more weight–an additional 1-2 lbs, on average–than formula-feeding moms.

In the past, prolactin’s stimulatory effect on appetite was adaptive. When living in an environment with a scarce or unpredictable supply of food, you need to save those precious fat reserves laid down during pregnancy for times of shortage.

But these days, the boost in appetite is arguably maladaptive, at least in developed countries, where food is plentiful and in constant supply. The shortage never comes, so women tend to hold onto their pregnancy fat reserves indefinitely.

Prolactin is just one piece of the weight loss problem. Lack of sleep is also a likely culprit.

Babies who are formula-fed are far more likely than breastfed babies to sleep through the night by 3-4 months of age, whereas breastfed babies tend to wake up to nurse in the middle of the night until 9-10 months of age.

Inadequate, broken sleep, such as that of new parents, wreaks havoc on the appetite. The body shifts into crisis mode, trying to conserve energy for what it assumes must be hard times. Energy levels tank. The hormones regulating appetite downshift into starvation mode: Levels of leptin, a hormone dampening appetite, drop, while levels of ghrelin, a hormone stimulating appetite, rise. Poor quality sleep increases activity in brain areas sensitive to rewarding, highly desirable foods, making it harder to resist high-calorie food.

Biology is not the only force working against weight loss while breastfeeding. For many women, breastfeeding, especially exclusive breastfeeding, poses serious logistical challenges to getting exercise. Breastfeeding on demand sucks away a tremendous amount of time. Who can fit in a workout when they are nursing every 2 to 3 hours for half an hour at a time?

Exclusive breastfeeding also makes it hard for other people to give you a break, so you can go to the gym or out for a walk.

This was certainly true for me. Both of my children refused, and I mean refused, to take a bottle. By 2 months of age, the mere sight of a bottle would send my son into hysterics. During the first 6 months after I gave birth, I could sneak away from him for at most an hour at a time.

The Bottom Line

Despite burning a considerable number of calories, breastfeeding has a negligible effect on body fat and total body weight for most well-nourished women.

The medical establishment, as well as many researchers, seems reluctant to admit this. For example, many of the research articles cited in this post have titles that suggest breastfeeding has a major impact on weight loss. Dig into their actual findings, though, and you find a different story: the differences in weight loss between breastfeeding and formula-feeding mothers are almost always small, and often vanish altogether when other factors, like age, gestational weight gain, and prepregnancy weight are taken into account.

Some of this reluctance may be because science can never “prove” a null result. It is always possible that the lack of an effect is due to poor study design, or poor measurement, or some other form of bias. A series of better-designed studies could find that breastfeeding leads to significant weight loss.

Still, when the vast majority of the evidence does not support the idea that breastfeeding helps women lose their pregnancy weight, major medical organizations like the AAP have no business stating otherwise.

The emphasis on breastfeeding for weight loss almost feels like a bait-and-switch. Because in fact, when it comes to holding onto extra pregnancy pounds, the biggest factor is not breastfeeding, but how much weight you gained during pregnancy.

What about you? Did breastfeeding help you lose your pregnancy weight?


Baker JL, Gamborg M, Heitmann BL, Lissner L, Sørensen TI, Rasmussen KM. Breastfeeding reduces postpartum weight retention. Am J Clin Nutr. 2008 Dec;88(6):1543-51. doi: 10.3945/ajcn.2008.26379.

Butte NF, Wong WW, Hopkinson JM. Energy requirements of lactating women derived from doubly labeled water and milk energy output. J Nutr 2001;131:53–8.

Butte NF, Hopkinson JM. Body composition changes during lactation are highly variable among women. J Nutr. 1998 Feb;128(2 Suppl):381S-385S.

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Dewey KG, Heinig MI. Nommsen LA, Lonnerdal B. Maternal versus infant factors related to breast milk intake and residual milk volume: the DARLING study. Pediatrics 1991:87:829-37.

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Gore SA, Brown DM, West DS. The role of postpartum weight retention in obesity among women: a review of the evidence. Ann Behav Med. 2003 Oct;26(2):149-59.

Gross BA, Eastman Cl. Prolactin and the return of ovulation in breastfeeding women. I Biosoc Sci l985;9(suppl):25-42. 14.

He X, Zhu M, Hu C, Tao X, Li Y, Wang Q, Liu Y. Breast-feeding and postpartum weight retention: a systematic review and meta-analysis. Public Health Nutr. 2015 Apr 21:1-9.

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Nehring I, Schmoll S, Beyerlein A, Hauner H, von Kries R. Gestational weight gain and long-term postpartum weight retention: a meta-analysis. Am J Clin Nutr. 2011 Nov;94(5):1225-31. doi: 10.3945/ajcn.111.015289.

Neville CE, McKinley MC, Holmes VA, Spence D, Woodside JV. The relationship between breastfeeding and postpartum weight change–a systematic review and critical evaluation. Int J Obes (Lond). 2014 Apr;38(4):577-90. doi: 10.1038/ijo.2013.132.

Oken E, Patel R, Guthrie LB, et al. Effects of an intervention to promote breastfeeding on maternal adiposity and blood pressure at 11.5 y postpartum: results from the Promotion of Breastfeeding Intervention Trial, a cluster-randomized controlled trial. The American Journal of Clinical Nutrition. 2013;98(4):1048-1056. doi:10.3945/ajcn.113.065300.

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17 thoughts on “Don't Count on Breastfeeding to Help You Shed Your Baby Weight”

  1. I breastfed each of my three children for a year, and I lost my pregnancy weight each time within that first year. Nothing noteworthy there, really.

    My interesting story of weight loss and breastfeeding, however, happened with my first. When she was three months old, I started caring for a friend’s three-month-old son.

    That baby? Would NOT take a bottle. Not, not, not. Every feeding was pure trauma for all concerned. After about a week of this, I looked at this hungry child, screaming against the bottle while snuggled against my milk-filled breasts, and thought, “Oh, why am I fighting this?”, and popped him on. Blissful silence ensued, punctuated only by gulps and sighs.

    I ‘fessed up when his mother arrived, fearing she might object, but in fact she was relieved. So, for the next three months (until my friend moved out of town), I nursed two babies during the day, five days a week.

    The weight? *Melted* off. I attributed it to the sudden doubling of my calorie needs for lactation. Maybe, having established my eating patterns, I didn’t increase my calorie intake? Or, because I nursed them tandem, I didn’t have a concomitant doubling of prolactin production?

    Whatever the reason, in that three-month period, from 3 to six months postpartum, I shed all — all — of my pregnancy weight gain. I found it fascinating.


  2. I lost a ton of weight when I STOPPED breastfeeding around 4 months. But that may be because my engorged 36H breasts probably weighed about 15lbs, so I lost a ton of weight in my breasts when I stopped.


  3. It was such a relief to find this post. I breastfed my son until 22 months. It was a great experience for the two of us, and I weaned him when it no longer felt as such. But those extra pregnancy pounds? Well, they actually increased during the first six months of breastfeeding, probably because I was sleep-deprived, not getting enough exercise and eating terribly. Many of my friends and colleagues, however, could swear breastfeeding had melted all their postpartum fat, and I felt like the utmost failure. I’m pregnant for the second time now, taking more care not to add too many pounds, and already knowing that I won’t be able to count on breastfeeding to help shed them.


  4. I breastfed exclusively and lost all of my pregnancy weight within 6 months. I sometimes didn’t lose for a few weeks and then suddenly lose a lot when he had a growth spurt (once whilst on holiday and eating loads). My son is now 7 months and I am 8kg (about 18lbs) lighter than pre-pregnancy. I have been trying to slow the weight loss, as since he was 6 months, I’ve been losing at least 1lb or 0.5kg a week and am getting too thin now. I am getting married this year and may have to buy a new dress because I can’t slow the weight loss despite eating a lot. My son is colicky after formula and weaning much slower than I was expecting. Have not been this skinny for years.

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  5. I’ve been trying to find info on this topic online, but am struggling. I weighed 48kg prepregnancy, and weighed 57kg at full term (birthing a healthy 3,4kg baby girl). Two weeks postpartum I was. Ack to 48kg. However, I have not been able to maintain my weight since then – which is surprising because I’ve never had difficulty maintaining my weight in the past. Ive been exclusively breastfeeding since her birth 12 weeks ago. I am convinced that breastfeeding is causing my weight gain. I won’t stop breastfeeding for this reason, obviously, but I need to know there’s a reason for it and that things will go back to normal after she’s born! My thighs have ballooned in size as have my upper arms. They were skinny when pregnant! Im not eating enough to be causing this…


  6. I’ve been trying to find info on this topic online, but am struggling. I weighed 48kg prepregnancy, and weighed 57kg at full term (birthing a healthy 3,4kg baby girl). Two weeks postpartum I was back to 48kg. However, I have not been able to maintain my weight since then and it’s been steadily increasing – which is surprising because I’ve never had difficulty maintaining my weight in the past. I’ve been exclusively breastfeeding since her birth 12 weeks ago. I am convinced that breastfeeding is causing my weight gain. I won’t stop breastfeeding for this reason, obviously, but I need to know there’s a reason for it and that things will go back to normal after she’s born! My thighs have ballooned in size as have my upper arms. They were skinny when pregnant! I’m not eating enough to be causing this…


  7. Here is my story I was very overweight at 5 feet tall I was 145 pounds when I got pregnant with my son fast forward to when he turned 10 months old I ended up 115 pounds with zero exercise in zero change to diet. MY body DID literally melt off my pregnancy weight AND MUCH MORE. how did I go from pre pregnancy weight of 145 to 115 with no diet and no exercise by the time he was 10 months old? Breastfeeding. I found results from my friends to be completely mixed. Half my breastfeeding friends lost pregnancy weight and beyond and the other half gained fat and water. I have no idea why. It’s a medical mystery to me.


  8. I exclusively breastfed my twins, and after an initial 40 lb weight loss in the first month postpartum, I actually gained weight while I nursed. Everyone told me the weight would just melt off, but I was very dismayed to discover the opposite. I was constantly, insatiably hungry. Despite my efforts to eat well and exercise, the extra pounds just wouldn’t budge. It wasn’t until the twins self-weaned at 15 months that I was able to see any real difference in my body. I am nursing my first singleton now, and there has been such a huge difference when it comes to my appetite and sleep/energy levels. I’m mostly maintaining my weight and not gaining, but it does seem like I retain extra fat stores in my upper arms and thighs while nursing. I’ve found that my body just looks different when I’m breastfeeding, and I’m learning to be OK with that.


  9. I think whether breastfeeding helps a woman lose weigh really varies from person to person, so while the overall statistics don’t bear out a benefit, some individual mothers benefit a lot and other mothers may actually gain weight while breastfeeding. The only way to tell which you will be is to try it yourself. With each of my boys I was back to my pre-pregnancy weight by doing nothing but breastfeeding (no exercise, no attempt to diet, nothing). I actually had my appetite drop after giving birth. With my first son I gained 50lbs. He weighed 9.5 lbs at birth and 22lbs at 4 months old; I am convinced he sucked all my pregnancy weight off. With my second son who only weighed 7.5lbs and was much smaller all of his infancy, I only gained about 25lbs. My third son weighed 8.3 lbs at birth, I gained somewhere around 35lbs and he remained between the other two in weight as he grew. I think my body understood the reserves I would need to feed each baby. However, I had a SIL who took off absolutely no weight while breastfeeding, even though she was carefully watching her diet and exercising.


  10. I agree that everyone is different. I have a three month old that is exclusively breastfed. I gained about 65 lbs during my pregnancy. This was due to a diet consisting of pizza and milkshakes, the only two things that could make my nausea and heartburn go away. I was about 133 lbs prepregnancy. I am losing a little over a pound a week and at this rate I am considering breastfeeding for life (joke). I think we have to be careful of what we eat. It is too easy to eat take out, junk food and sweets, especially at the beginning when you aren’t sleeping, your body is still recovering and your baby is so needy. I gave myself the first two weeks postpartum to eat what I liked. After that, I watched what I ate. Many people brought sweets, pastries and cookies to my house after I gave birth. I threw them away. It’s hard enough being home alone with a screaming baby and I didn’t want the temptation of eating the first thing I saw. I also did not diet or starve myself. I eat high fat food, like whole milk, whole milk yoghurt, meat and eggs. At about 13 weeks postpartum I also incorporated a small amount of excercise, about 15 min of strength training twice a week. My baby has also been sleeping through the night since she was six weeks old and I still breastfeed on demand. We have off days where she will wake once or twice, but it is no longer the norm. I don’t think this all has to do with luck.


  11. I have had 3 and I only lost weight properly after I stopped breastfeeding, even though I was eating really healthy low calorie foods and exercising lots. It was so frustrating to have everyone tell me I was obviously eating too much 😡


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