Most women gain weight during pregnancy – typically only a few pounds, but pronounced and permanent approximately one-fifth of the time.
Given that a high body mass index increases the risk of complications and disease during and after pregnancy, the trend towards greater weight gain poses a serious public health issue. Women who are significantly overweight even before pregnancy are particularly vulnerable.
A 12-week study of 68 overweight or obese lactating women by researchers at Sahlgrenska Academy, University of Gothenburg, evaluated a dietary treatment method that produced an average of 10 percent weight loss.
The weight loss remained at one-year follow-up.
“The treatment involved providing the subjects with individual advice and support,” says Fredrik Bertz, the Sahlgrenska researcher who led the study. “The goal was for them to gradually reduce their consumption of sweets, snacks and soft drinks, choose low-sugar, low-fat food, fill half their plates with vegetables, cut back on the size of their servings, and weigh themselves on a regular basis.
“The results were unexpectedly encouraging. Not only did the women lose considerable weight, but they did not regain half of it during the first year as is normally the case when people go off a diet. The use of sophisticated methods also permitted us to confirm the effect of the treatment on calorie intake, metabolic rate and body composition (ratio of muscle to fat).”
Apart from ensuring the best possible nutrition for a baby, nursing helps a woman lose weight. In Mr. Bertz’s view, however, breastfeeding is not enough to produce the substantial reductions that overweight and obese women need.
“Little knowledge was previously available,” he says, “about the best way of treating obesity after pregnancy – diet, exercise or a combination of the two – to ensure permanent weight loss.
“This study has generated scientific data for developing new policies and making wise clinical choices. Our hope is that the results will help women achieve permanent weight loss after pregnancy.”
Surprisingly, the subjects who exercised in addition to receiving dietary treatment did not lose more weight.
“The reason may be is that all of the participants in the study were already relatively active,” Mr. Bertz says, “so that they were not in a position to significantly increase their metabolic rate. Previous research has found that exercise alone falls short as a strategy for losing weight.”
The article, entitled “Diet and Exercise Weight-loss Trial in Lactating Overweight and Obese Women,” appeared in the October 2012 issue of the American Journal of Clinical Nutrition.
FACTS ABOUT THE STUDY:
The study consisted of two phases: 12-week treatment, followed by nine months during which the subjects were on their own. Each subject was randomly assigned to one of four groups.
One group received individual dietary counseling based on Swedish nutritional recommendations, as well as instructions to weigh themselves three times a week in order to adjust their calorie intake. The target was weight loss of 1.1 pounds per week. Another group received individual exercise counseling and a pulsometer in order to adjust the intensity of milder exercise sessions. A third group received both dietary and exercise counseling, while the fourth (control) group did not receive any counseling at all.
Fredrik Bertz, Sahlgrenska Academy, University of Gothenburg
Cell: +46 733 803 842
Phone: +46 31 786 3708