A randomized clinical trial of home-based exercise combined with a slight caloric restriction on obesity prevention among women
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.
Section snippets
Materials and methods
This randomized clinical study was primarily aimed at small weight loss comparing a low with a high glycemic index diet. Results did not indicate a difference between the low and high glycemic index diets on weight change. The full description and results of dietary intervention have been published elsewhere (Sichieri et al., 2007). The trial had a factorial design, with half of the dietary intervention receiving also orientation for home-based exercise during 12 months, and the other half only
Results
Baseline characteristics of the women randomly assigned to the two groups are shown in Table 1. Most of the baseline characteristics showed no difference between the groups, but age showed a small difference and BMI and HDL cholesterol showed statistically significant difference (p < 0.05). Losses to follow-up during the 1-year period were 45% for CG and 42% for the HB group (Fig. 1). No differences between completers and drop-outs were found for any baseline characteristics (p > 0.20). The number
Discussion
The major finding of the present study was that a small volume of home-based exercise in addition to a slight caloric restriction promoted a higher reduction in body weight during the first 6 months in comparison with a caloric restriction only. However, this change was not sustainable during one year of follow-up. In addition, the exercise program did correlate with a substantial increase in serum HDL cholesterol levels, even at 12 months, indicating continued compliance and resulting in
Conflict of interest statement
The authors declare that there are no conflicts of interest.
Acknowledgments
Research relating to this study was funded by grant R03 TW005773-03 from National Institutes of Health (NIH) and grant 500404/2003-8 from Brazilian National Research Council-CNPq.
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