Use of Low-Carbohydrate Diets During Lactation: Implications for Mothers and Infants

Diet or exercise, or both, for weight reduction in women after childbirth

BACKGROUND

Weight retention after pregnancy may contribute to obesity. It is known that diet and exercise are recommended components of any weight loss programme in the general population. However, strategies to achieve healthy body weight among postpartum women have not been adequately evaluated.

OBJECTIVES

The objectives of this review were to evaluate the effect of diet, exercise or both for weight reduction in women after childbirth, and to assess the impact of these interventions on maternal body composition, cardiorespiratory fitness, breastfeeding performance and other child and maternal outcomes.

SEARCH METHODS

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (31 January 2012) and LILACS (31 January 2012). We scanned secondary references and contacted experts in the field. We updated the search of the Cochrane Pregnancy and Childbirth Group's Trials Register on 30 April 2013 and added the results to the awaiting classification section of the review.

SELECTION CRITERIA

All published and unpublished randomised controlled trials (RCTs) and quasi-randomised trials of diet or exercise or both, among women during the postpartum period.

DATA COLLECTION AND ANALYSIS

Both review authors independently assessed trial quality and extracted data. Results are presented using risk ratio (RR) for categorical data and mean difference (MD) for continuous data. Data were analysed with a fixed-effect model. A random-effects model was used in the presence of heterogeneity.

MAIN RESULTS

Fourteen trials were included, but only 12 trials involving 910 women contributed data to outcome analysis. Women who exercised did not lose significantly more weight than women in the usual care group (two trials; n = 53; MD -0.10 kg; 95% confidence interval (CI) -1.90 to 1.71). Women who took part in a diet (one trial; n = 45; MD -1.70 kg; 95% CI -2.08 to -1.32), or diet plus exercise programme (seven trials; n = 573; MD -1.93 kg; 95% CI -2.96 to -0.89; random-effects, T² = 1.09, I² = 71%), lost significantly more weight than women in the usual care group. There was no difference in the magnitude of weight loss between diet alone and diet plus exercise group (one trial; n = 43; MD 0.30 kg; 95% CI -0.06 to 0.66). The interventions seemed not to affect breastfeeding performance adversely.

AUTHORS' CONCLUSIONS

Evidence from this review suggests that both diet and exercise together and diet alone help women to lose weight after childbirth. Nevertheless, it may be preferable to lose weight through a combination of diet and exercise as this improves maternal cardiorespiratory fitness and preserves fat-free mass, while diet alone reduces fat-free mass. This needs confirmation in large trials of high methodological quality. For women who are breastfeeding, more evidence is required to confirm whether diet or exercise, or both, is not detrimental for either mother or baby.

Diet or exercise, or both, for weight reduction in women after childbirth

BACKGROUND

Weight retention after pregnancy may contribute to obesity. It is known that diet and exercise are recommended components of any weight loss programme in the general population. However, strategies to achieve healthy body weight among postpartum women have not been adequately evaluated.

OBJECTIVES

The objectives of this review were to evaluate the effect of diet, exercise or both for weight reduction in women after childbirth, and to assess the impact of these interventions on maternal body composition, cardiorespiratory fitness, breastfeeding performance and other child and maternal outcomes.

SEARCH STRATEGY

We searched the Cochrane Pregnancy and Childbirth Group's Trials Register (September 2006) and LILACS. We scanned secondary references and contacted experts in the field.

SELECTION CRITERIA

All published and unpublished randomised controlled trials (RCT) and quasi-randomised trials of diet or exercise or both, among women during the postpartum period.

DATA COLLECTION AND ANALYSIS

Three review authors independently assessed trial quality and extracted data. Results are presented using relative risk for categorical data and weighted mean difference (WMD) for continuous data. Data were analysed with a fixed-effect model. A random-effects model was used in the presence of heterogeneity.

MAIN RESULTS

Six trials involving 245 women were included. Women who exercised did not lose significantly more weight than women in the usual care group (one trial; n = 33; WMD 0.00 kg; 95% confidence interval (CI) -8.63 to 8.63). Women who took part in a diet (one trial; n = 45; WMD -1.70 kg; 95% CI -2.08 to -1.32), or diet plus exercise programme (four trials; n = 169; WMD -2.89 kg; 95% CI -4.83 to -0.95), lost significantly more weight than women in the usual care. There was no difference in the magnitude of weight loss between diet and diet plus exercise group (one trial; n = 43; WMD 0.30 kg; 95% CI -0.60 to 0.66). The interventions seemed not to affect breastfeeding performance adversely.

AUTHORS' CONCLUSIONS

Preliminary evidence from this review suggests that dieting and exercise together appear to be more effective than diet alone at helping women to lose weight after childbirth, because the former improves maternal cardiorespiratory fitness level and preserves fat-free mass, while diet alone reduces fat-free mass. For women who are breastfeeding, more evidence is required to confirm whether diet or exercise, or both, is not detrimental for either mother or baby. Due to insufficient available data, additional research, with larger sample size, is needed to confirm the results.