A randomized clinical trial of home-based exercise combined with a slight caloric restriction on obesity prevention among women

Abstract

Objective

The study investigated the effectiveness of home-based exercise combined with a slight caloric restriction on weight change during 12 months in non-obese women.

Methods

A randomized clinical trial with a factorial design was conducted from 2003 to 2005. Two hundred three middle-aged women (Rio de Janeiro/Brazil), 25–45 years, were randomly assigned to one of two groups: control (CG) and home-based exercise (HB). The HB group received a booklet on aerobic exercise that could be practiced at home (3 times/week–40 min/session), in low-moderate intensity, during 12 months. Both groups received dietary counseling aimed at a slight energy restriction of 100–300 calories per day.

Results

The HB experienced a greater weight loss in the first 6 months (−1.4 vs. −0.8 kg; p = 0.04), but after 12 months there was no differences between groups (−1.1 vs. −1.0; p = 0.20). Of the serum biochemical markers, HDL cholesterol showed major change, with an increase at month 12 of 18.3 mg/dl in the HB compared to 9.5 in the CG (p < 0.01).

Conclusion

Home-based exercise promoted greater weight reduction during the first 6 months after which no further benefits are observed. Continuous favorable changes in HDL cholesterol after 1 year suggest that home-based exercise promote health benefits.

Introduction

Although small-changes approach has been suggested to be an effective way to curb the obesity epidemic (Hill, 2009), others have questioned this approach (Swinburn et al., 2009). Dietary restriction combined with physical activity (PA) may represent an effective strategy to promote weight loss and reduce fat mass (Jakicic and Otto, 2005, Mediano et al., 2007). In a review article, Hansen et al. (2007) reinforced the role of PA on weight control, although many studies reported that the inclusion of PA in addition to a restriction in energy intake did not appear to facilitate weight loss (Christ et al., 2004, Miller et al., 1997). Despite these controversies, PA is considered to be a key part of the therapy for obesity, both for its effects on weight loss, and for the improvements it promotes in metabolic parameters such as insulin sensitivity and lipid profile (Bensimhon et al., 2006, Votruba et al., 2000).

Few studies have investigated the role of small amounts of exercise in preventing obesity (Kraus et al., 2001, Slentz et al., 2005). Since weight loss is difficult to maintain, weight gain prevention or prevention of obesity may be a useful strategy. In a 4-year observational research in the Health Professionals Follow-up Study on predictors of weight change, Coakley et al. (1998) found that a decrease in 1.5 h per week in physical activity predicted a gain of 0.6 kg, whereas an increase in activity over 1.5 h per week predicted a weight loss of 0.9 kg. More recently, Williams et al. (2007) evaluated weight control practices and the resulting 2-year weight changes among middle-aged women and found that only the combination of diet and exercise prevented mean weight gain. The mean weight gain of the cohort in that study was of 1.19 kg over the 2-year period.

An important aspect of PA on prevention and treatment of obesity is the low adherence to formal programs, limiting the efficacy of these strategies (Rhodes et al., 2009). Many individual are unable to engage in a formal program due to difficulty with transportation or not having adequate financial resources justifying the counseling of home-based exercise, but few studies compared this approach to traditional ones. Perri et al. (1997) compared the effectiveness of center- versus home-based exercise in a sample of sedentary, middle-aged obese women undergoing behavior weight loss treatment and found a better adherence to exercise in a home-based group after 12 months of follow-up. Krousel-Wood et al. (2008) found a BMI reduction in persons with diabetes, submitted to 3 months of home-based exercise intervention, with high adherence rates, about 80%. Therefore, home-based exercises could be an option that would improve PA adherence.

The purpose of this study was to investigate the effectiveness of home-based exercise combined with a slight caloric restriction on maintenance of small weight change in non-obese women. Secondary outcomes were changes in waist circumference and biochemical markers. We hypothesized that addition of home-based exercise to a slight caloric restriction could facilitate weight loss.