摘要：Objectives. We examined the viability and efficacy of a known quantity of exercise in facilitating weight loss among previously sedentary or irregularly active overweight and obese adult women residing in a slum ( favela ) in Brazil. Methods. In this randomized controlled trial, 156 women were randomized to a control or intervention group (78 in each group). Exercise was supervised, consisting of three 50-minute aerobic sessions each week for 6 months. Results. Ninety-one percent (71) of the participants in the intervention group completed 6 months of the exercise program. At 6 months, women in the treatment group showed significant reduction in weight (mean = −1.69 kg; 95% confidence interval [CI] = −2.36,−1.03) and body mass index (mean = −0.63 kg/m2; 95% CI = −0.97, −0.30) compared with controls ( P for both < .001). Conclusions. A moderately intense, structured exercise program resulted in modest weight loss in women when sustained for 6 months. The deleterious effect of obesity on health has been well documented over the last century. 1 Obesity and overweight have been implicated in the etiology of a wide range of chronic diseases, including coronary heart disease, 2 – 4 stroke, 5 hypertension, 6 diabetes, 7 selected cancers, 8 and certain psychiatric conditions, 9 all of which demand considerable health care expenditure. Other, more-subtle negative consequences of obesity have been described: adults who were overweight as adolescents report lower prevalence of marriage, levels of educational attainment, and income, 10 , 11 presumably as a result of discrimination in their professional and social lives. The rise in obesity is as clear as its various health and social consequences, with increases reported both in high-income countries 12 and in developing societies. 13 Recent evidence from Brazil also suggests that the current trend in adult obesity levels is upward and is more pronounced among the most socioeconomically disadvantaged groups. 14 Thus, from a public health perspective, the socioeconomically disadvantaged may be a particularly important target for behavior modification. Although obesity is a complex metabolic disorder, it is ultimately the result of energy intake and expenditure. Therefore, the fundamental goal in treatment of obese persons is to attain negative energy balance by reducing food intake or increasing levels of physical activity, or both. 15 Systematic reviews examining the effect of exercise on weight loss in adults have been conducted, 16 – 22 resulting in the finding that exercise alone, particularly of higher intensity, results in some weight reduction. Many studies examining obesity and overweight are characterized by methodological shortcomings such as an absence of intention-to-treat analyses, small sample size, short duration of follow-up, and failure to verify the quantity of physical exertion of study participants. We are unaware of any randomized controlled trial of exercise as a treatment for obesity in women carried out in a developing country, where the resources needed to conduct such an investigation are obviously scarce. Our purpose was to examine the viability and efficacy of conducting a trial of a known quantity of exercise in facilitating weight loss among previously sedentary, overweight women residing in a typical slum ( favela ) in Brazil.
