Review: dietary restriction, with or without aerobic exercise, promotes weight loss in postpartum women
A R Amorim
Correspondence to: Dr A R Amorim, Copenhagen University Hospital, Copenhagen, Denmark;
Are diet and/or exercise effective for weight reduction in postpartum women?
Cochrane Pregnancy and Childbirth Group’s Trial Register (including searches of Cochrane Central Register of Controlled Trials, Medline, 30 journals, and proceedings of major conferences) (September 2006), LILACS (2006), reference lists, and experts.
Study selection and assessment:
randomised controlled trials (RCTs) and quasi-randomised trials that evaluated interventions involving diet (advice, counselling, or prescription of a calorie-restricted diet) and/or exercise (counselling or structured programmes) in postpartum women (⩽12 mo after birth of a healthy singleton term infant) ⩾18 years of age who were overweight, obese, or had gained excessive weight during pregnancy. Excluded were studies involving women who were underweight before pregnancy, exercise interventions for pelvic or back pain or urinary incontinence, or interventions combined with medication. 6 RCTs (n = 245) met the selection criteria; duration of the intervention ranged from 11 days to 11 months. Quality of individual trials was assessed based on allocation concealment, completeness of follow-up, and blinding of outcome assessors.
body weight, percentage body fat, fat-free mass, cardiorespiratory fitness, milk volume, and infant growth.
Dietary restriction reduced body weight more than usual care (table) but also reduced fat-free mass; groups did not differ for change in percentage body fat. Supervised aerobic exercise did not increase weight loss more than usual care (table) but did increase cardiorespiratory fitness (2 RCTs, n = 53); groups did not differ for change in percentage body fat or fat-free mass. Dietary restriction plus aerobic exercise reduced body weight more than usual care (table) and increased the proportion of women who returned to prepregnancy weight (2 RCTs, n = 102) or achieved a healthy weight (2 RCTs, n = 63). The combined intervention also reduced percentage body fat (3 RCTs, n = 107) and improved cardiorespiratory fitness (2 RCTs, n = 63); groups did not differ for change in fat-free mass. Dietary restriction plus aerobic exercise did not increase weight loss more than dietary restriction alone (table) but prevented the loss of fat-free mass; groups did not differ for change in percentage body fat. No intervention was found to have a negative effect on milk production or infant growth.
Dietary restriction, with or without an aerobic exercise programme, promotes weight loss in postpartum women. The combination of dieting and exercise improves cardiorespiratory fitness and preserves fat-free mass.
Amorim AR, Linne YM, Lourenco PMC. Diet or exercise, or both, for weight reduction in women after childbirth. Cochrane Database Syst Rev 2007;(3):CD005627.
Clinical impact ratings: Family/General practice 5/7; Obstetric nursing 5/7
A priority for nurses who work with women in the postpartum period is to enhance health through reducing weight retention. Amorim et al reported that women who completed a prescribed diet or diet plus physical activity intervention successfully lost weight, whereas those who received general education about diet and exercise did not. The review provides information about effects of dieting on breastfeeding performance, reporting that none of the interventions negatively affected milk production. It integrates what is already known about the effects of exercise and diet in the general population with new evidence that aerobic exercise alone may not affect weight loss.
The findings of the review support interventions that preserve lean body mass and improve cardiovascular fitness; however, they must be interpreted carefully because the included studies were few in number, had small sample sizes, and varied widely in onset and duration of the interventions. For example, the trial comparing diet plus exercise with diet alone began at 8–16 weeks postpartum and lasted for only 11 days to avoid compromising breast milk volume and composition. The safe levels for duration and degree of calorie restriction and increased physical activity are not yet clearly established. Therefore, there remains a need to determine the most appropriate patterns of diet and physical activity to help prevent maternal obesity and promote infant growth and development.
Giving new mothers realistic information about weight loss is challenging because pregnancy and the postpartum period are different for each woman; thus, diet and physical activity experiences must be considered in light of unique personal and social influences. The review was not able to evaluate the influence of characteristics such as age, parity, education, income, racial and ethnic background, support, family history, personal weight history, smoking, type of birth, and employment outside the home during the postpartum period. In addition, there was no consideration of other relevant factors, such as motivation to lose weight and the burden of the intervention (eg, stress and fatigue). Further research is needed to enable the development of effective, individualised postpartum personal fitness and nutrition regimens for overweight and obese mothers.