McMillian-Price J, Petocz P, Atkinson F, O’Neill K, Samman S, Steinbeck K et al.. Comparison of 4 diets of varying glycemic load on weight loss and cardiovascular risk reduction in overweight and obese young adults. Arch Intern Med 166, 1466-1475

Human Nutrition Unit, University of Sydney, Sydney, Australia.
Archives of Internal Medicine (Impact Factor: 17.33). 07/2006; 166(14):1466-75. DOI: 10.1001/archinte.166.14.1466
Source: PubMed


Despite the popularity of low-glycemic index (GI) and high-protein diets, to our knowledge no randomized, controlled trials have systematically compared their relative effects on weight loss and cardiovascular risk.
A total of 129 overweight or obese young adults (body mass index, > or =25 [calculated as weight in kilograms divided by the square of height in meters]) were assigned to 1 of 4 reduced-fat, high-fiber diets for 12 weeks. Diets 1 and 2 were high carbohydrate (55% of total energy intake), with high and low GIs, respectively; diets 3 and 4 were high protein (25% of total energy intake), with high and low GIs, respectively. The glycemic load was highest in diet 1 and lowest in diet 4. Changes in weight, body composition, and blood chemistry profile were studied.
While all groups lost a similar mean +/- SE percentage of weight (diet 1, -4.2% +/- 0.6%; diet 2, -5.5% +/- 0.5%; diet 3, -6.2% +/- 0.4%; and diet 4, -4.8% +/- 0.7%; P = .09), the proportion of subjects in each group who lost 5% or more of body weight varied significantly by diet (diet 1, 31%; diet 2, 56%; diet 3, 66%; and diet 4, 33%; P = .01). Women on diets 2 and 3 lost approximately 80% more fat mass (-4.5 +/- 0.5 [mean +/- SE] kg and -4.6 +/- 0.5 kg) than those on diet 1 (-2.5 +/- 0.5 kg; P = .007). Mean +/- SE low-density-lipoprotein cholesterol levels declined significantly in the diet 2 group (-6.6 +/- 3.9 mg/dL [-0.17 +/- 0.10 mmol/L]) but increased in the diet 3 group (+10.0 +/- 3.9 mg/dL [+0.26 +/- 0.10 mmol/L]; P = .02). Goals for energy distribution were not achieved exactly: both carbohydrate groups ate less fat, and the diet 2 group ate more fiber.
Both high-protein and low-GI regimens increase body fat loss, but cardiovascular risk reduction is optimized by a high-carbohydrate, low-GI diet.

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    • "Intensive lifestyle intervention has shown to be effective in reducing risk for T2DM in high risk individuals [6,7]. Conventional diets for primary prevention of T2DM consistently support energy-restricted, low-fat, and high–complex carbohydrate regime to achieve weight loss [8,9]. However, such interventions have shown limited success in reducing postpartum weight in women after GDM [10]. "
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    ABSTRACT: BACKGROUND: Gestational Diabetes Mellitus (GDM) increases risks for type 2 diabetes and weight management is recommended to reduce the risk. Conventional dietary recommendations (energy-restricted, low fat) have limited success in women with previous GDM. The effect of lowering Glycaemic Index (GI) in managing glycaemic variables and body weight in women post-GDM is unknown. OBJECTIVE: To evaluate the effects of conventional dietary recommendations administered with and without additional low-GI education, in the management of glucose tolerance and body weight in Asian women with previous GDM. METHOD: Seventy seven Asian, non-diabetic women with previous GDM, between 20- 40y were randomised into Conventional healthy dietary recommendation (CHDR) and low GI (LGI) groups. CHDR received conventional dietary recommendations only (energy restricted, low in fat and refined sugars, high-fibre). LGI group received advice on lowering GI in addition. Fasting and 2-h post-load blood glucose after 75g oral glucose tolerance test (2HPP) were measured at baseline and 6 months after intervention. Anthropometry and dietary intake were assessed at baseline, three and six months after intervention. The study is registered at the Malaysian National Medical Research Register (NMRR) with Research ID: 5183 RESULTS: After 6 months, significant reductions in body weight, BMI and waist-to-hip ratio were observed only in LGI group (P<0.05). Mean BMI changes were significantly different between groups (LGI vs. CHDR: -0.6 vs. 0kg/m2, P= 0.03). More subjects achieved weight loss >=5% in LGI compared to CHDR group (33% vs. 8%, P=0.01). Changes in 2HPP were significantly different between groups (LGI vs. CHDR: median (IQR): -0.2(2.8) vs. +0.8 (2.0) mmol/L, P=0.025). Subjects with baseline fasting insulin>=2muIU/ml had greater 2HPP reductions in LGI group compared to those in the CHDR group (-1.9+/-0.42 vs. +1.31+/-1.4 mmol/L, P<0.001). After 6 months, LGI group diets showed significantly lower GI (57+/-5 vs. 64+/-6, P<0.001), GL (122+/-33 vs. 142+/-35, P=0.04) and higher fibre content (17+/-4 vs.13+/-4g, P<0.001). Caloric intakes were comparable between groups. CONCLUSION: In women post-GDM, lowering GI of healthy diets resulted in significant improvements in glucose tolerance and body weight reduction as compared to conventional low-fat diets with similar energy prescription.
    Full-text · Article · May 2013 · Nutrition Journal
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    • "Persistently high blood glucose and insulin as a result of a diet high in high GI carbohydrate may cause metabolic abnormalities giving rise to dyslipidemia that in turn increase the risk of stroke risk. Randomized trials have shown that low-GI and low-GL diets affect plasma concentrations of LDL cholesterol [26], [27], HDL cholesterol [28], triglycerides [29], [30], markers of inflammation [29] and thrombosis [30], and insulin resistance [31], in ways expected to reduce the risk of cerebrovascular disease. However, the observed effect of dietary interventions have been relatively modest and have not been observed consistently across trials [9]. "
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    ABSTRACT: Studies on the association of stroke risk to dietary glycemic index (GI) and glycemic load (GL) have produced contrasting results. To investigate the relation of dietary GI and GL to stroke risk in the large EPIC-Italy cohort (EPICOR) recruited from widely dispersed geographic areas of Italy. We studied 44099 participants (13,646 men and 30,453 women) who completed a dietary questionnaire. Multivariable Cox modeling estimated adjusted hazard ratios (HRs) of stroke with 95% confidence intervals (95%CI). Over 11 years of follow-up, 355 stroke cases (195 ischemic and 83 hemorrhagic) were identified. Increasing carbohydrate intake was associated with increasing stroke risk (HR = 2.01, 95%CI = 1.04-3.86 highest vs. lowest quintile; p for trend 0.025). Increasing carbohydrate intake from high-GI foods was also significantly associated with increasing stroke risk (HR 1.87, 95%CI = 1.16-3.02 highest vs. lowest, p trend 0.008), while increasing carbohydrate intake from low-GI foods was not. Increasing GL was associated with significantly increasing stroke risk (HR 2.21, 95%CI = 1.16-4.20, highest vs. lowest; p trend 0.015). Dietary carbohydrate from high GI foods was associated with increased both ischemic stroke risk (highest vs. lowest HR 1.92, 95%CI = 1.01-3.66) and hemorrhagic stroke risk (highest vs. lowest HR 3.14, 95%CI = 1.09-9.04). GL was associated with increased both ischemic and hemorrhagic stroke risk (HR 1.44, 95%CI = 1.09-1.92 and HR 1.56, 95%CI = 1.01-2.41 respectively, continuous variable). In this Italian cohort, high dietary GL and carbohydrate from high GI foods consumption increase overall risk of stroke.
    Full-text · Article · May 2013 · PLoS ONE
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    • "Perhaps this coupled with the aforementioned spread was enough to allow for anthropometric differences between protein groups. Additionally in regard to the McMillan-Price et al. study [35], participants were stratified: 1) lower protein/higher GI; 2) lower protein/lower GI; 3) higher protein/higher GI; and 4) higher protein/lower GI [35]. In women, higher protein/higher GI lost significantly more body and fat mass than lower protein/higher GI. "
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    ABSTRACT: A large volume of human clinical data supports increased dietary protein for favorable changes to body composition, but not all data are conclusive. The aim of this review is to propose two theories, "protein spread theory" and "protein change theory" in an effort to explain discrepancies in the literature. Protein spread theory proposed that there must have been a sufficient spread or % difference in g/kg/day protein intake between groups during a protein intervention to see body composition and anthropometric differences. Protein change theory postulated that for the higher protein group, there must be a sufficient change from baseline g/kg/day protein intake to during study g/kg/day protein intake to see body composition and anthropometric benefits. Fifty-one studies met inclusion criteria. In studies where a higher protein intervention was deemed successful there was, on average, a 58.4% g/kg/day between group protein intake spread versus a 38.8% g/kg/day spread in studies where a higher protein diet was no more effective than control. The average change in habitual protein intake in studies showing higher protein to be more effective than control was +28.6% compared to +4.9% when additional protein was no more effective than control. Providing a sufficient deviation from habitual intake appears to be an important factor in determining the success of additional protein in weight management interventions. A modest increase in dietary protein favorably effects body composition during weight management interventions.
    Full-text · Article · Sep 2012 · Nutrition & Metabolism
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