An 18-mo randomized trial of a low-glycemic-index diet and weight change in Brazilian women

Abstract

Background: Despite interest in the glycemic index diets as an approach to weight control, few long-term evaluations are available. Objective: The objective was to investigate the long-term effect of a low-glycemic-index (LGI) diet compared with that of a highglycemic-index (HGI) diet; all other dietary components were equal. Design: After a 6-wk run-in, we randomly assigned 203 healthy women [body mass index (in kg/m 2 ): 23-30] aged 25-45 y to an LGI or an HGI diet with a small energy restriction. The primary outcome measure was weight change at 18 mo. Secondary outcomes included hunger and fasting insulin and lipids. Results: Despite requiring a run-in and the use of multiple incentives, only 60% of the subjects completed the study. The difference in glycemic index between the diets was Ȃ35-40 units (40 compared with 79) during all 18 mo of follow-up, and the carbohydrate intake from energy remained at Ȃ60% in both groups. The LGI group had a slightly greater weight loss in the first 2 mo of follow-up (Ҁ0.72 compared with Ҁ0.31 kg), but after 12 mo of follow-up both groups began to regain weight. After 18 mo, the weight change was not significantly different (P ҃ 0.93) between groups (LGI: Ҁ0.41 kg; HGI: Ҁ0.26 kg). A greater reduction was observed in the LGI diet group for triacylglycerol (difference ҃ Ҁ16.4 mg/dL; P ҃ 0.11) and VLDL cholesterol (difference ҃ Ҁ3.7 mg/dL; P ҃ 0.03). Conclusions: Long-term weight changes were not significantly different between the HGI and LGI diet groups; therefore, this study does not support a benefit of an LGI diet for weight control. Favorable changes in lipids confirmed previous results.Am J Clin Nutr 2007;86:707-13. KEY WORDSLow-glycemic-index diet, weight change, Brazilian women

Reducing risk factors in overweight adult users of the family health strategy of the Distrito Federal

“…Similar studies that encouraged the consumption of healthy foods and physical activity also reduced cardiovascular risk 22,26,27 . However, one of the problems faced by health-promoting programs is that attendance decreases as the intervention period increases, resulting in significant sample losses during the intervention as seen in this and other studies 28,29 . A study conducted in the Distrito Federal provided nutrition education to a group of overweight and obese individuals for three months but only 45.8% of the sample had excellent attendance 28 .…”

“…Such intervention studies should not only compare dropout and completer profiles but also include intention-to-treat analysis 29 , preventing completers' positive results from being overestimated because of dropouts' possibly negative results. Therefore, this methodological control showed that despite the average attendance, the intervention promoted improvements in the study parameters, especially the anthropometric ones.…”

Dietary glycaemic index, glycaemic load and subsequent changes of weight and waist circumference in European men and women

“…Although some clinical intervention studies observed a beneficial effect of reducing dietary GI and GL on weight loss, 8,12 others did not. [9][10][11] Few long-term cohort studies among free-living populations have been conducted to explore associations between GI or GL and weight change. 15,16 In these two cohort studies, a positive association between GI, but not GL, and weight change has been observed, at least in subgroups.…”

“…8 However, this conclusion has not been consistently confirmed by RCTs published thereafter. [9][10][11][12] Short duration, difficulties in adhering to the prescribed diets, and a high dropout rate are well-known drawbacks of clinical intervention studies. Furthermore, dietary factors promoting weight loss among obese individuals may not be appropriate to prevent weight gain in the long term.…”

Diet assessment in the Brazilian Longitudinal Study of Adult Health (ELSA-Brasil): Development of a food frequency questionnaire

“…In addition to investigating this issue in a population rather different from those of other longitudinal studies, ELSA-Brasil will test hypotheses generated in Brazilian cross-sectional studies that contemplate diet as a factor of exposure to certain diseases, such as the influence of combining rice and beans on obesity 20,21 .…”