A Randomized Clinical Trial of Home-based Exercise Combined With a Slight Caloric Restriction on Obesity Prevention Among Women

Overview

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. In addition the investigators evaluate the effects of baseline insulin resistance on modulation of weight change. 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. 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). At baseline the non-IR group (n=121) compared to IR (n=64) had similar values of BMI (26.7 vs. 26.3 p=0.21), but statistically significant lower values of waist, glucose, insulin and HOMA-IR, as expected. When the group non-IR and IR were further stratified by GI diet, there were no differences according to diet in both groups. Women classified as IR at baseline had greater weight loss after 12 months of follow-up (-1.62 kg vs. -1.08 kg; p=0.01), and HB exercise helped to reduce weight only among NIR women (-1.51 vs. -0.68; p=0.04); no differences were observed between intervention groups for IR women (-1.54 vs. -1.66; p=0.24). There were no differences between IR and NIR groups for lipid profile after adjustment for weight changes. During follow-up, changes were more pronounced among those women in the high GI diet. These differences were statistically significant for weight and BMI and were greater among the IR compared to the non-IR. Changes in HOMA-IR after 3 months of follow-up were different comparing non-IR with IR at baseline. The IR had a reduction in the HOMA-IR, whereas in the non-IR this value increased (-0.73 vs. +0.37; p=\<0.001). Also this reduction was greater among high compared to low GI diet (p=0.04).