Association between dietary glycemic index, glycemic load, and body mass index in the Inter99 study: is underreporting a problem?
ABSTRACT The few studies examining the potential associations between glycemic index (GI), glycemic load (GL), and body mass index (BMI) have provided no clear pictures. Underreporting of energy intake may be one explanation for this.
We examined the associations between GI, GL, and BMI by focusing on the confounding factor of total energy intake and the effect of exclusion of low energy reporters (LERs).
This was a cross-sectional study of 6334 subjects aged 30-60 y. Dietary intake was estimated from a food-frequency questionnaire. GI and GL were estimated by using white bread as the reference food. Underreporting of energy intake was assessed as reported energy intake divided by basal metabolic rate (EI/BMR); LERs were defined as those having an EI/BMR < 1.14. Univariate and multiple linear regression models were used to test for associations between GI, GL, and BMI. The confounders were sex, age, smoking, physical activity, alcohol intake, and energy intake. All analyses were conducted on 1) the entire population and 2) a subsample excluding LERs.
In the univariate analyses of the entire population, GL was inversely associated with BMI. No association was observed for GI. After full adjustment (including energy intake), both GI and GL were positively associated with BMI. When LERs were excluded, GL was positively associated with BMI in all analyses, and GI was positively associated with BMI in the multiple analyses.
We showed a positive association between GI, GL, and BMI. Energy adjustment and the exclusion of LERs significantly affected the results of the analysis; thus, we stress the importance of energy adjustment.
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ABSTRACT: Although several studies have assessed the influence of the glycemic index on body weight and blood pressure among adults, limited evidence exists for the pediatric age population. In the current study, we compared the effects of low glycemic index (LGI) diet to the healthy nutritional recommendation (HNR)-based diet on obesity and blood pressure among adolescent girls in pubertal ages. This 10-week parallel randomized clinical trial comprised of 50 overweight or obese and sexually mature girls less than 18 years of age years, who were randomly assigned to LGI or HNR-based diet. Macronutrient distribution was equivalently prescribed in both groups. Blood pressure, weight and waist circumference were measured at baseline and after intervention. Of the 50 participants, 41 subjects (include 82%) completed the study. The GI of the diet in the LGI group was 42.67 ± 0.067. A within-group analysis illustrated that in comparison to the baseline values, the body weight and body mass index (not waist circumference and blood pressure) decreased significantly after the intervention in both groups (P = 0.0001). The percent changes of the body weight status, waist circumference and blood pressure were compared between the two groups and the findings did not show any difference between the LGI diet consumers and those in the HNR group. In comparison to the HNR, LGI diet could not change the weight and blood pressure following a 10-week intervention. Further longitudinal studies with a long-term follow up should be conducted in this regard.Nutrition research and practice 10/2013; 7(5):385-92. · 0.97 Impact Factor
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ABSTRACT: OBJECTIVE: Several studies assessed the effect of glycemic index (GI) and glycemic load (GL) on energy intake in children but findings are not consistent in this regard. The aim of this study is to summarize and assess the evidence for the effect of GI and GL on energy intake by conducting a meta-analysis on published randomized clinical trials. METHOD: Our search process was conducted in PUBMED, Web of Science, and Google Scholar databases. The following keywords were searched in any part of published articles: "glycemic index" OR "glycaemic index" OR "glycemic load" OR "glycaemic load" OR "energy intake" AND "child" OR "children" OR "adolescent" OR "youth." RESULTS: We gathered 5099 articles. Non-clinical trial studies that did not intervene by GI or GL or those not assessing energy intake as a dependent variable and those that were conducted on patients over age 18 y were excluded. Each included study was evaluated three times and the exclusion criteria was checked. Eventually, six studies from 1999 to 2012 met the criteria (213 participants ages 4-17.5 y). There is heterogeneity in the study's participants in the present paper. Children with type 2 diabetes, obesity, or normal-weight children were recruited in different studies. Overall effect of consuming low GI (LGI) and low GL (LGL) meals on energy intake was not significant. Subgroup analysis showed that LGI (not LGL) meals decreased subsequent energy intake, whereas heterogeneity was significant in the LGI group of studies. Although a slight asymmetry was shown by Begg's funnel plot, the Egger's asymmetry was not significant. We did not find any evidence of publication bias for studies assessing the effect of low GI or GL meals on energy intake. CONCLUSION: Consuming LGI diet (not LGL) has favorable effect on reducing energy intake and obesity, subsequently.Nutrition 06/2013; · 2.86 Impact Factor
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ABSTRACT: Several evidences have been reported so far in terms of the relationship between obesity and glycemic index and glycemic load in children. However, the number of review studies that have dealt with recent findings is quite low. The purpose of present study is to review the existing evidences in this regard. FIRST OF ALL, THE PHRASES: "Glycaemic index", "Glycaemic load", "Glycemic index" OR "Glycemic load" accompanied by one of the words: "Adolescent", "Young", "Youth" "Children" OR "Child" were searched in texts of articles existing in ISI and PUBMED databases which were obtained out of 1001 articles. Among these, some articles, which reviewed the relationship of obesity with glycemic index and glycemic load, were selected. Finally, 20 articles were studied in current review study. The majority of cross-sectional studies have found children's obesity directly linked with glycemic index and glycemic load; however, cohort studies found controversial results. Also, the intervention studies indicate the negative effect of glycemic index and glycemic load on obesity in children. Published evidences reported inconsistent results. It seems that existing studies are not sufficient and more studies are needed in this regard.Advanced biomedical research. 01/2014; 3:47.