Glycemic index and glycemic load in relation to body mass index and waist to hip ratio

Interaction of MC4R rs17782313 variants and dietary carbohydrate quantity and quality on basal metabolic rate and general and central obesity in overweight/obese women: a cross-sectional study

BACKGROUND

Recent studies have shown that dietary carbohydrate quantity and quality as well as genetic variants may contribute to determining the metabolic rate and general and central obesity. This study aimed to examine interactions between melanocortin 4 receptor gene (MC4R) rs17782313 and dietary carbohydrate intake, glycemic index (GI), and glycemic load (GL) on body mass index (BMI), waist circumferences (WC), basal metabolic rate (BMR), and BMR/kg in overweight/obese women.

METHODS

A total of 282 Iranian women (BMI ≥ 25) aged 18-56 years were enrolled in this cross-sectional study. All participants were assessed for blood parameters, body composition, BMR, and dietary intake. Dietary carbohydrate intake, GI, and GL were determined using a valid, reliable 147-item food frequency questionnaire. MC4R rs17782313 was genotyped by the restriction fragment length polymorphism (PCR-RFLP) method.

RESULTS

After adjustment for age and energy intake, significant interactions were observed between carbohydrate intake and MC4R rs17782313 in terms of BMI (P Interaction = 0.007), WC (P Interaction = 0.02), and BMR/kg (P Interaction = 0.003) in this way that higher carbohydrate intake, compared with lower intake, was associated with an increase in BMI and WC for individuals with C allele carriers (TC + CC genotypes), while related to an increase in BMR/kg for those carrying the TT genotype. No significant interaction was found between MC4R rs17782313 and GI and GL on BMI, WC, BMR/kg, and BMR.

CONCLUSIONS

Interactions between the MC4R rs17782313 and carbohydrate intake probably can have an effect on BMI, WC, and BMR/kg in overweight/obese women.

Perspective: Does Glycemic Index Matter for Weight Loss and Obesity Prevention? Examination of the Evidence on "Fast" Compared with "Slow" Carbs

High-glycemic index (high-GI) foods (so-called fast carbs) have been hypothesized to promote fat storage and increase risk of obesity. To clarify whether dietary GI impacts body weight, we searched PubMed and the Cochrane Database of Systematic Reviews for observational studies reporting associations between BMI and dietary GI, and for meta-analyses of randomized controlled trials (RCTs) comparing low-GI and high-GI diets for weight loss. Data on 43 cohorts from 34 publications, totaling 1,940,968 adults, revealed no consistent differences in BMI when comparing the highest with the lowest dietary GI groups. In the 27 cohort studies that reported results of statistical comparisons, 70% showed that BMI was either not different between the highest and lowest dietary GI groups (12 of 27 cohorts) or that BMI was lower in the highest dietary GI group (7 of 27 cohorts). Results of 30 meta-analyses of RCTs from 8 publications demonstrated that low-GI diets were generally no better than high-GI diets for reducing body weight or body fat. One notable exception is that low-GI diets with a dietary GI at least 20 units lower than the comparison diet resulted in greater weight loss in adults with normal glucose tolerance but not in adults with impaired glucose tolerance. While carbohydrate quality, including GI, impacts many health outcomes, GI as a measure of carbohydrate quality appears to be relatively unimportant as a determinant of BMI or diet-induced weight loss. Based on results from observational cohort studies and meta-analyses of RCTs, we conclude that there is scant scientific evidence that low-GI diets are superior to high-GI diets for weight loss and obesity prevention.

Dietary glycemic index and glycemic load in relation to general obesity and central adiposity among adults

BACKGROUND & AIMS

Although the association between dietary Glycemic Index (GI), Glycemic Load (GL) and general/abdominal obesity has extensively been examined, limited data are available in this regard in developing countries. The aim of this study was to examine the association between dietary GI and GL with general and abdominal obesity.

METHODS

This cross-sectional study was conducted among adults in Isfahan, Iran. Dietary GI and GL were assessed using a validated dish-based 106-item semi-quantitative food frequency questionnaire (DS-FFQ). Data regarding height, weight and waist circumference were collected using a self-reported questionnaire. Overweight or obesity was defined as body mass index ≥25 kg/m², and abdominal obesity was defined as waist circumference ≥80 cm for women and ≥94 cm for men.

RESULTS

There was no significant association between dietary GI and GL and general obesity. After adjustment for potential confounders, participants in the highest quintile of dietary GI had a higher chance for abdominal obesity (OR: 1.29; 95% CI: 1.01-1.64), compared with those in the lowest quintile. No significant association was observed between dietary GL and abdominal obesity. After adjustment for potential confounders, women in the top quintile of dietary GI had higher chance for abdominal obesity compared with those in the bottom quintile (OR: 1.48, 95% CI: 1.02-2.15). No significant association was found between dietary GI and abdominal obesity among men. We failed to find any significant association between dietary GI and general obesity in either gender [Comparing top vs. bottom quintiles, for men: OR: 0.97; 95% CI: 0.74-1.29 and for women: OR: 1.01; 95% CI: 0.75-1.40]. No significant association was found between dietary GL and general [for men: OR: 1.13; 95% CI: 0.85-1.49 and for women: OR: 1.01; 95% CI: 0.76-1.35], as well as abdominal obesity [for men: OR: 1.21; 95% CI: 0.88-1.67 and for women: OR: 1.25; 95% CI: 0.88-1.77].

CONCLUSIONS

We found a significant positive association between dietary GI and abdominal obesity. When we conducted analyses stratified by gender, we also observed such association in women, but not in men. No other significant associations were observed between dietary GI and GL with general or abdominal obesity.

The Association Between Dietary Glycemic Index and Glycemic Load and a Body Shape and Fat Distribution Among Apparently Healthy Iranian Adults

OBJECTIVE

The role of dietary glycemic index (GI) and glycemic load (GL) in the development of obesity has been debated globally. The relationship with body shape and fat distribution was examined in this cross-sectional association study among apparently healthy Iranian adults.

METHODS AND MATERIALS

A study population of 265 (126 males and 139 females) aged 18-55 years participated in this cross-sectional study from the communities of Tehran based on cluster sampling. GI and GL were assessed by the 147-item food frequency questionnaire (FFQ) completed by a trained dietitian. Weight, height, waist circumference (WC), and hip circumference of the participants were measured, and body mass index (BMI), waist-to-hip ratio (WHR), and A Body Shape Index (ABSI) were further calculated. Fat mass and fat-free mass were also measured using a body composition analyzer, and fat mass index (FMI) and fat-free mass index (FFMI) were then calculated. Multivariate regression models were fitted to assess the association between GI/GL and fat distribution measures such as FMI, FFMI, WC, BMI, WHR, and ABSI, considering potential confounding factors such as sex, age, BMI, and physical activity.

RESULTS

There was a statistically significant inverse association between GL and WC, BMI, and ABSI found in the adjusted model. GL was inversely associated with WC for both the adjusted model (p-trend = 0.027) and the crude model. Also, an inverse association was seen between GL and BMI (p-trend = 0.019) in the adjusted model but a marginal association in the crude model. GL was also inversely associated with ABSI (p-trend = 0.089) in the highest tertile.

CONCLUSION

Dietary GL but not GI is inversely associated with fat distribution measures such as WC, BMI, and ABSI in the study population. This result may suggest a beneficial role of higher-GL diets in the prevention of obesity.

Association of lower body mass index with increased glycemic variability in patients with newly diagnosed type 2 diabetes: a cross-sectional study in China

Previous studies have indicated that the pathogenesis of diabetes differs between obese and lean patients. We investigated whether newly diagnosed Chinese diabetic patients with different body mass indices (BMIs) have different glycemic variability, and we assessed the relationship between BMI and glycemic variability. This was a cross-sectional study that included 169 newly diagnosed and drug-naïve type 2 diabetic patients (mean age, 51.33 ± 9.83 years; 110 men). The clinical factors and results of the 75-g oral glucose tolerance test were all recorded. Glycemic variability was assessed using continuous glucose monitoring. Compared with overweight or obese patients (BMI ≥ 24 kg/m2), underweight or normal-weight patients (BMI < 24 kg/m2) had higher levels of blood glucose fluctuation parameters, particularly in terms of mean amplitude of glycemic excursion (MAGE 6.64 ± 2.38 vs. 5.67 ± 2.05; P = 0.007) and postprandial glucose excursions (PPGEs) (PPGE at breakfast, 7.72 ± 2.79 vs. 6.79 ± 2.40, P = 0.028; PPGE at lunch, 5.53 ± 2.70 vs. 5.07 ± 2.40, P = 0.285; PPGE at dinner, 5.96 ± 2.24 vs. 4.87 ± 2.50, P = 0.008). BMI was negatively correlated with glycemic variability (r = -0.243, P = 0.002). On multiple linear regression analyses, BMI (β = -0.231, P = 0.013) and Insulin Secretion Sensitivity Index-2 (β = -0.204, P = 0.048) were two independent predictors of glycemic variability. In conclusion, lower BMI was associated with increased glycemic variability, characterized by elevated PPGEs, in newly diagnosed Chinese type 2 diabetic patients.

Dietary Glycemic Index and Glycemic Load Are Positively Associated with Risk of Developing Metabolic Syndrome in Middle-Aged and Elderly Adults

OBJECTIVES

To evaluate how glycemic index (GI) and glycemic load (GL) are associated with the metabolic syndrome (MetS) and its features in middle-aged and elderly adults at high cardiovascular risk.

DESIGN

Prospective, longitudinal, population-based cohort.

SETTING

PREvención con DIeta MEDiterránea study.

PARTICIPANTS

Men and women (N = 6,606) divided into three age groups (<65, 65-74, ≥75).

MEASUREMENTS

Energy and nutrient intake was evaluated using a validated 137-item food frequency questionnaire. MetS and its features were defined in accordance with the criteria of the American Heart Association and National Heart, Lung, and Blood Institute.

RESULTS

A positive association was observed between GI and MetS prevalence in the youngest and middle age groups for participants without diabetes mellitus, but no relationship was found for those with diabetes mellitus. During the median follow-up of 4.8 years, higher GI and GL were related to greater risk of MetS in the middle age group, independent of the presence of diabetes mellitus. Changes in dietary GI were associated with risk of developing the high fasting glucose component of the MetS in the oldest age category, and changes in dietary GL were associated with risk of developing abdominal obesity, hypertriglyceridemia, low high-density lipoprotein cholesterol, and high blood pressure in the youngest age category.

CONCLUSION

Dietary GI and GL have a potential role in the development of MetS and associated clinical features, with particular age-dependent considerations.

Glycemic load, glycemic index, bread and incidence of overweight/obesity in a Mediterranean cohort: the SUN project

BACKGROUND

To evaluate prospectively the relationship between white, or whole grain bread, and glycemic index, or glycemic load from diet and weight change in a Mediterranean cohort.

METHODS

We followed-up 9 267 Spanish university graduates for a mean period of 5 years. Dietary habits at baseline were assessed using a semi-quantitative 136-item food-frequency questionnaire. Average yearly weight change was evaluated according to quintiles of baseline glycemic index, glycemic load, and categories of bread consumption. We also assessed the association between bread consumption, glycemic index, or glycemic load, and the incidence of overweight/obesity.

RESULTS

White bread and whole-grain bread were not associated with higher weight gain. No association between glycemic index, glycemic load and weight change was found.White bread consumption was directly associated with a higher risk of becoming overweight/obese (adjusted OR (≥2 portions/day) versus (≤1 portion/week): 1.40; 95% CI: 1.08-1.81; p for trend: 0.008). However, no statistically significant association was observed between whole-grain bread, glycemic index or glycemic load and overweight/obesity.

CONCLUSIONS

Consumption of white bread (≥2 portions/day) showed a significant direct association with the risk of becoming overweight/obese.

Mediterranean diet pyramid: a proposal for Italian people

Bread was a staple in the traditional Mediterranean diet of the early 1960s, as well as nowadays; however, it was a stone ground sourdough bread in Nicotera and probably in the Greek cohorts of the Seven Countries Study. In the present review, the nutritional characteristics of this food are analyzed in relation to its protective effects on coronary heart disease, metabolic diseases and cancer. According to our traditions, cultural heritage and scientific evidence, we propose that only cereal foods with low glycemic index (GI) and rich in fiber have to be placed at the base of the Mediterranean diet pyramid, whereas refined grains and high GI starchy foods have to be sited at the top.

Glycemic index, glycemic load and childhood obesity: A systematic review

BACKGROUND

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.

MATERIALS AND METHODS

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.

RESULTS

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.

CONCLUSION

Published evidences reported inconsistent results. It seems that existing studies are not sufficient and more studies are needed in this regard.

Mediterranean diet and glycaemic load in relation to incidence of type 2 diabetes: results from the Greek cohort of the population-based European Prospective Investigation into Cancer and Nutrition (EPIC)

AIMS/HYPOTHESIS

The role of diet in the prevention of diabetes remains uncertain. The aim of this study was to investigate two different dietary aspects, i.e. adherence to the Mediterranean diet and glycaemic load (GL), in relation to diabetes occurrence.

METHODS

We analysed data from the Greek cohort of the population-based European Prospective Investigation into Cancer and Nutrition (EPIC). From a total of 22,295 participants, actively followed for a median of 11.34 years, 2,330 cases of incident type 2 diabetes were recorded. All participants completed a validated, interviewer-administered semi-quantitative food frequency questionnaire at enrolment. From this information, we calculated a ten point Mediterranean diet score (MDS), reflecting adherence to the traditional Mediterranean diet, as well as the dietary GL. We estimated HRs and the corresponding 95% CIs of diabetes using Cox proportional hazards regression models adjusted for potential confounders.

RESULTS

A higher MDS was inversely associated with diabetes risk (HR 0.88 [95% CI 0.78, 0.99] for MDS ≥ 6 vs MDS ≤ 3). GL was positively associated with diabetes (HR 1.21 [95% CI 1.05, 1.40] for the highest vs the lowest GL quartile). A significant protection of about 20% was found for a diet with a high MDS and a low GL.

CONCLUSIONS/INTERPRETATION

A low GL diet that also adequately adheres to the principles of the traditional Mediterranean diet may reduce the incidence of type 2 diabetes.

Associations of dietary glycaemic index and glycaemic load with food and nutrient intake and general and central obesity in British adults

Inconsistent associations between dietary glycaemic index (GI) and glycaemic load (GL) and body fatness may be partly due to differences in the underlying dietary patterns or energy under-reporting. In the present study, we examined the cross-sectional associations of dietary GI and GL with food and nutrient intake and general and central obesity, accounting for energy under-reporting. The subjects were 1487 British adults aged 19-64 years. Dietary intake was assessed using a 7 d weighed dietary record. Breads and potatoes were the positive predictive foods for dietary GI, while fruit, other cereals and dairy products were the negative predictors. These foods were similarly identified in the analysis of only acceptable reporters (AR; ratio of reported energy intake:estimated energy requirement within 0·665-1·335) and under-reporters (UR; ratio < 0·665). Dietary GL was closely correlated with carbohydrate intake. Multiple linear regression analyses showed that dietary GI was independently associated with a higher risk of general obesity (BMI ≥ 30 kg/m²) and central obesity (waist circumference ≥ 102 cm in men and ≥ 88 cm in women). Dietary GL was also associated with general (only women) and central obesity. Similarly, in the analysis of AR, the GI showed positive associations with general and central obesity, and, only in women, the GL showed positive associations with general and central obesity. Conversely, in the analysis of UR, the associations were generally weaker and many of them failed to reach statistical significance. In conclusion, we found independent positive associations of dietary GI and GL with general and central obesity in British adults.