Research Shows Breastfeeding Linked to Better Long-Term Weight Outcomes for Mothers

Breastfeeding may shape your health decades later-not just in the months after childbirth.

A new study from the University of Oslo suggests that women who breastfeed for at least three months gain significantly less weight later in life. Published in the American Journal of Clinical Nutrition, the research followed over 170,000 participants from the long-running Women and Health Study in Norway, tracking weight changes from early adulthood into middle age.

The findings reveal a clear long-term benefit. Women who breastfed each child for three to 15 months gained up to 6.5 kilograms less over time compared to those who breastfed for shorter durations. The effect was most pronounced among women who were already overweight or obese before pregnancy. Among women with normal weight, the difference was smaller but still notable—up to 3 kilograms less weight gain over the years.

Researchers say breastfeeding likely contributes to this effect by increasing energy expenditure, as the body uses additional calories to produce milk. However, the relationship is not straightforward. Increased appetite during breastfeeding may offset some of the calorie burn, meaning outcomes can vary between individuals.

Interestingly, the association between breastfeeding and lower long-term weight was strongest among women who had children after 1980. This group is considered more reflective of modern lifestyles, including diet and breastfeeding practices, making the findings especially relevant today.

Beyond individual benefits, the study highlights broader public health implications. Supporting breastfeeding could play a role in reducing long-term weight gain and associated risks such as cardiovascular disease. At the same time, researchers emphasize the importance of personalized care, noting that women—especially those with overweight or obesity—may need additional support after childbirth.

Overall, the study reinforces that breastfeeding is not just beneficial for infants, but may also offer lasting health advantages for mothers well into later life.

REFERENCE: Skammelsrud, T. B., et al. (2026). Breastfeeding duration and maternal weight change through adulthood in a population-based cohort study. The American Journal of Clinical Nutrition. DOI: 10.1016/j.ajcnut.2025.101134. https://ajcn.nutrition.org/article/S0002-9165(25)00726-9/fulltext