No magic pill to postpartum weight loss

UAlberta research debunks breastfeeding-weight loss myth.

Women lose weight and change their body composition after giving birth in highly individual ways, according to new University of Alberta research.

Rhonda Bell, along with nutritional science professors Linda McCargar and Carla Prado, authored a study that tracked weight loss, body composition and energy expenditure postpartum in 50 women.

Previous studies have found that roughly half of all women in developed countries gain weight during their pregnancy in excess of Health Canada's recommended total weight gain for women with an average body weight of between 25 and 35 pounds. As well, those who start pregnancy with a body mass index (BMI) over 25 are more likely to experience high weight gain.

"The excess weight increases the risk of health complications for baby and mom, and makes it more likely that women will keep some of that weight after they deliver," said Rhonda Bell, a UAlberta nutritional science professor.

Study participants experienced one of four body composition change scenarios up to nine months postpartum:

  • Gained fat, gained lean muscle

  • Gained fat, lost lean muscle

  • Lost fat, lost lean muscle

  • Lost fat, gained lean muscle

"The findings suggest losing baby weight will occur differently for every women and she will need to adapt her weight loss strategy as needed, including cutting out unnecessary calories, adding in physical activity and taking a view toward an extended timeline," explained Bell.

Health Canada does not provide guidelines for how best to lose weight postpartum.

"It's important for women to lose weight at a gradual pace, about half a pound to one pound weekly after the first six to 12 weeks," advised Bell, adding that women need to meet but not exceed basic nutritional requirements postpartum and throughout lactation while the body repairs tissue.

"Eating well and being physically active will help the body reach a new, healthy body composition and level of metabolism."

She added a common misconception is that breastfeeding mobilizes fat to return to a pre-pregnancy fat distribution and body weight.

"A lot of women believe that if they breastfeed they'll lose fat but many find the weight doesn't come off as quickly as they'd like," said Bell. "our research shows weight loss and fat loss aren't as simple as just breastfeeding after giving birth. All the women lost weight, but their body compositions were all over the map," she said.

This study is one of many under UAlberta's ENRICH research program looking at how to support healthy pregnancy across diverse groups of women.