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Aim: To compare the impact of two long-term weight-maintenance diets, a high protein (HP) and low glycaemic index (GI) diet versus a moderate protein (MP) and moderate GI diet, combined with either high intensity (HI) or moderate intensity physical activity (PA), on the incidence of type 2 diabetes (T2D) after rapid weight loss., Materials and Methods: A 3-year multicentre randomized trial in eight countries using a 2 x 2 diet-by-PA factorial design was conducted. Eight-week weight reduction was followed by a 3-year randomized weight-maintenance phase. In total, 2326 adults (age 25-70 years, body mass index ≥ 25 kg/m 2 ) with prediabetes were enrolled. The primary endpoint was 3-year incidence of T2D analysed by diet treatment. Secondary outcomes included glucose, insulin, HbA1c and body weight., Results: The total number of T2D cases was 62 and the cumulative incidence rate was 3.1%, with no significant differences between the two diets, PA or their combination. T2D incidence was similar across intervention centres, irrespective of attrition. Significantly fewer participants achieved normoglycaemia in the HP compared with the MP group (P < .0001). At 3 years, normoglycaemia was lowest in HP-HI (11.9%) compared with the other three groups (20.0%-21.0%, P < .05). There were no group differences in body weight change (-11% after 8-week weight reduction; -5% after 3-year weight maintenance) or in other secondary outcomes., Conclusions: Three-year incidence of T2D was much lower than predicted and did not differ between diets, PA or their combination. Maintaining the target intakes of protein and GI over 3 years was difficult, but the overall protocol combining weight loss, healthy eating and PA was successful in markedly reducing the risk of T2D. This is an important clinically relevant outcome., (© 2020 The Authors. Diabetes, Obesity and Metabolism published by John Wiley & Sons Ltd.)

There is no question that elevated postprandial glycemia is a significant driver of common chronic diseases globally [...].

Dietary glycaemic index (GI) and glycaemic load (GL) are indices used to quantify the effect of carbohydrate quality and quantity on postprandial glycaemia. GI/GL-health associations are widely studied but data on the validity of integrated GI/GL measurements are scarce. We evaluated the performance of a food-frequency questionnaire (FFQ) specifically developed to assess GI/GL. In total, 263 Dutch men and 212 women (aged 55 ± 11 years) completed a 58-item GI-FFQ, an 183-item general-FFQ and a 2-day 24 h-recall and donated blood for glycated haemoglobin (HbA1c) determination. The level of agreement between these methods was evaluated by (1) cross-classification, (2) correlations and (3) Bland and Altman plots. The three dietary assessment methods provided comparable mean intake estimates for total carbohydrates (range: 214⁻237 g/day), mono/disaccharides (100⁻107 g/day), polysaccharides (114⁻132 g/day), as well as bread, breakfast cereals, potatoes, pasta, rice, fruit, dairy, cakes/cookies and sweets. Mean (±SD) GI estimates were also comparable between the GI-FFQ (54 ± 3), general-FFQ (53 ± 4) and 24 h-recalls (53 ± 5). Mean (±SD) GI-FFQ GL (117 ± 37) was slightly lower than the general-FFQ GL (126 ± 38) and 24 h-recalls GL (127 ± 37). Classification of GI in quartiles was identical for the GI-FFQ and general-FFQ for 43% of the population ( r = 0.58) and with 24 h-recalls for 35% of the population (de-attenuated r = 0.64). For GL, this was 48% ( r = 0.65) and 44% (de-attenuated r = 0.74). Correlations between GI and HbA1c were low ( r = -0.09 for GI-FFQ, r = -0.04 for general-FFQ and r = 0.07 for 24 h-recalls). In conclusion, compared to a general-FFQ and 24 h-recalls, the GI-FFQ showed a moderate to good relative validity for carbohydrates, carbohydrate-rich foods and GI/GL. No metric predicted HbA1c., Competing Interests: The authors declare no conflict of interest. The founding sponsors had no role in the design of the study; in the collection, analyses, or interpretation of data; in the writing of the manuscript and in the decision to publish the results.

Maternal diet and gestational hyperglycaemia have implications for offspring health. Leptin ( LEP ) and fat mass and obesity-associated ( FTO ) alleles are known to influence body fat mass in humans, potentially via effects on appetite. We hypothesized that expression of Fto , Lep , and other appetite-related genes ( Argp, Npy, Pomc, Cart, Lepr ) in the offspring of female mice are influenced by the glycaemic index (GI) of carbohydrates in the maternal diet. C57BL/6 mice were randomly assigned to low or high GI diets and mated with chow-fed males at eight weeks of age. Male pups were weaned at four weeks and randomly divided into two groups, one group following their mother's diet (LL and HH), and one following the standard chow diet (LC and HC) to 20 weeks. Fto expression was 3.8-fold higher in the placenta of mothers fed the high GI diet ( p = 0.0001) and 2.5-fold higher in the hypothalamus of 20-week old offspring fed the high GI (HH vs. LL, p < 0.0001). By contrast, leptin gene ( Lep ) expression in visceral adipose tissue was 4.4-fold higher in four-week old offspring of low GI mothers (LC vs. HC, p < 0.0001) and 3.3-fold higher in visceral adipose tissue of 20-week old animals (LL vs. HH, p < 0.0001). Plasma ghrelin and leptin levels, and hypothalamic appetite genes were also differentially regulated by maternal and offspring diet. These findings provide the first evidence in an animal model that maternal high GI dietary carbohydrates that are digested and absorbed faster may contribute to programming of appetite in offspring.

Background/objectives: German-style breads are recommended as a lower glycaemic index (GI) alternative, yet little data is available. Our aim was to test the GI and insulin index (II) of four breads and rolls commonly consumed in Germany., Subjects/methods: Four German bread products were tested for their GI and II in 12 healthy subjects according to the International Standard Organization guidelines., Results: Only the wholemeal rye bread with visible intact grains and sunflower seeds was identified as low GI (GI=55). Both the wholemeal spelt wheat (GI=63) and the rye wheat sourdough bread (GI=62) were classified as medium GI, whereas soft pretzel was high GI (GI=80, P<0.05 compared with other products). The II of soft pretzels (II=102) was also highest and differed significantly from wholemeal rye (II=70) and rye sourdough bread (II=72) but not from wholemeal spelt wheat (II=77)., Conclusions: Contrary to popular belief, these German-style breads are medium to high GI, with the exception of the rye bread with intact grains and seeds. The results highlight the need to test, rather than 'guestimate', the GI of local products, and develop a broader range of low-GI breads.

This paper describes the compilation of a special edition of the AUSNUT2011-2013 food composition database that includes glycemic index (GI) values. A 6-step, systematic methodology was used to assign GI to 5644 foods included in AUSNUT2011-2013. A total of 1752 (31%) foods were assigned a GI of 0 owing to low carbohydrate content; 363 (6%) had a direct match in 1 of the 4 data tables used; 1738 (31%) were assigned the GI of a 'closely related' food item; 1526 (27%) were assigned the weighted mean GI of ingredients; 205 (4%) were assigned the median GI of their corresponding food subgroup; 49 (<1%) were assigned a GI of 0 because they were not a significant source of carbohydrate in typical diets; and 5 (<1%) were assigned a default GI. We propose that this database should be used for all future Australian GI research until a subsequent version/update is compiled.

Background and Aims: The positive and negative health effects of dietary carbohydrates are of interest to both researchers and consumers., Methods: International experts on carbohydrate research held a scientific summit in Stresa, Italy, in June 2013 to discuss controversies surrounding the utility of the glycemic index (GI), glycemic load (GL) and glycemic response (GR)., Results: The outcome was a scientific consensus statement which recognized the importance of postprandial glycemia in overall health, and the GI as a valid and reproducible method of classifying carbohydrate foods for this purpose. There was consensus that diets low in GI and GL were relevant to the prevention and management of diabetes and coronary heart disease, and probably obesity. Moderate to weak associations were observed for selected cancers. The group affirmed that diets low in GI and GL should always be considered in the context of diets otherwise understood as healthy, complementing additional ways of characterizing carbohydrate foods, such as fiber and whole grain content. Diets of low GI and GL were considered particularly important in individuals with insulin resistance., Conclusions: Given the high prevalence of diabetes and pre-diabetes worldwide and the consistency of the scientific evidence reviewed, the expert panel confirmed an urgent need to communicate information on GI and GL to the general public and health professionals, through channels such as national dietary guidelines, food composition tables and food labels., (Copyright © 2015 Elsevier B.V. All rights reserved.)

Background/objectives: Consumption of formula in place of human milk may produce differences in postprandial glycaemia and insulinaemia that contribute to metabolic programming in the first year of life. The objective of the current study was to determine glycaemic and insulinaemic responses to human milk compared with a typical commercial formula, and then compare 11 other formulas., Subjects/methods: On separate mornings in random order, 10 healthy breastfeeding mothers consumed 25 g available carbohydrate portions of their own milk, a formula and reference food (25 g glucose on two occasions). In the second study, 10 different healthy subjects consumed 25 g available carbohydrate portions of 11 different commercial formulas and three reference foods (25 g glucose on three occasions). Fingerpick blood samples were taken at regular intervals over 2 h, and the glycaemic index (GI) and insulin index determined according to a standardised protocol., Results: There were no significant differences in postprandial glycaemia or insulinaemia after human milk vs a typical formula (P = 0.3). Both produced a low GI (mean ± s.e.m.: 38 ± 7 vs 34 ± 7, respectively) and high insulin index (87 ± 14 vs 94 ± 16). The GI and insulin indices of the other formulas ranged from 18 ± 3 to 67 ± 6 and 53 ± 9 to 209 ± 33, respectively., Conclusions: Human milk and a typical formula elicit similar postprandial glycaemic and insulinaemic responses, but there is a wide range of responses to other formulas.

Potatoes are a popular source of dietary carbohydrate worldwide and are generally considered to be a high glycemic index (GI) food. Potato starch characteristics play a key role in determining their rate of digestion and resulting glycemic response. Starches isolated from seven potato cultivars with different GI values, including a low GI cultivar (Carisma), were examined for relative crystallinity, granule size distribution, amylopectin chain length, and thermal and pasting properties. Starch from the Carisma cultivar was more thermally stable and more resistant to gelatinization, with significantly higher (p < 0.05) pasting temperature and differential scanning calorimetry (DSC) gelatinization onset, peak and conclusion temperatures, compared to the other cultivars. Differences between the potatoes in the other properties measured did not align with the GI ranking. Thermal analysis and starch pasting properties may be useful indicators for preliminary identification of potato cultivars that are digested slowly and have a lower GI.

Objective: Technological processes may influence the release of glucose in starch. The aim of this study was to compare the metabolic response and the kinetics of appearance of exogenous glucose from 2 cereal products consumed at breakfast., Methods: Twenty-five healthy men were submitted to a randomized, open, crossover study that was divided into 2 parts: 12 of the 25 subjects were included in the "isotope part," and the 13 other subjects were included in the "glycemic part." On test days, subjects received biscuits (low glycemic index [GI], high slowly available glucose [SAG]) or extruded cereals (medium GI, low SAG) as part of a breakfast similar in terms of caloric and macronutrient content. The postprandial phase lasted 270 minutes., Results: The rate of appearance (RaE) of exogenous glucose was significantly lower after consumption of biscuits in the first part of the morning (90-150 minutes) than after consumption of extruded cereals (p ≤ 0.05). Conversely, at 210 minutes, it was significantly higher with biscuits (p ≤ 0.01). For the first 2 hours, plasma glucose and insulin were significantly lower after biscuits during the glycemic part. C-peptide plasma concentrations were significantly lower at 90, 120, and 150 minutes after ingestion of the biscuits (p ≤ 0.05)., Conclusion: The consumption of biscuits with a high content of slowly digestible starch reduces the appearance rate of glucose in the first part of the morning and prolongs this release in the late phase of the morning (210 minutes). Our results also emphasize that modulation of glucose availability at breakfast is an important factor for metabolic control throughout the morning in healthy subjects due to the lowering of blood glucose and insulin excursions.

&#160;The aim of this study was to examine the monetary cost of dietary change among pregnant women before and after receiving low glycaemic index (GI) dietary advice. The pregnant women in this study were a subgroup of participants in the Pregnancy and Glycaemic Index Outcomes (PREGGIO) study. Twenty women from the low GI dietary advice group, who had completed their pregnancies, were randomly chosen. All these women had completed three day food records at 12&#8211;16 weeks and again around 36 weeks of gestation. Consumer food prices were applied to recorded dietary intake data. The mean &#177; SD GI of the diet reduced from 55.1 &#177; 4.3 to 51.6 &#177; 3.9 (p = 0.003). The daily cost of the diet (AUD) was 9.1 &#177; 2.7 at enrolment and 9.5 &#177; 2.1 prior to delivery was not significantly different (p = 0.52). There were also no significant differences in the daily energy intake (p = 0.2) or the daily cost per MJ (p = 0.16). Women were able to follow low GI dietary advice during pregnancy with no significant increase in the daily costs.

Background: Puberty is a so-called critical period for overweight development and is characterized by physiological insulin resistance during mid-puberty. This study addressed the hypothesis that habitual consumption of a diet inducing higher levels of postprandial glycemia or insulinemia during puberty may have an unfavorable effect on the body composition in young adulthood., Methods: Multivariate regression analysis was performed on 262 participants of the Dortmund Nutritional and Anthropometric Longitudinally Designed Study with at least two 3-day weighed dietary records during puberty (baseline: girls 9-14 years; boys 10-15 years) and anthropometric measurements in young adulthood (18-25 years). A published dietary glycemic index was assigned to each carbohydrate-containing food. Similarly, each food was assigned a food insulin index (insulinemic response to a 1 MJ portion of food relative to 1 MJ of glucose) using 121 values measured at Sydney University., Results: Dietary glycemic index or glycemic load during puberty was not related to body composition in young adulthood. In contrast, a higher dietary insulin index and a higher dietary insulin load during puberty were associated with higher levels of percentage of body fat (%BF) in young adulthood, even after adjustment for early life, socioeconomic and nutritional factors; %BF in energy-adjusted tertiles of dietary insulin index were 22.9 (95% confidence intervals (CI): 21.6, 24.1), 24.5 (23.2, 25.7), 24.7 (23.5, 25.9) %, P (for trend)=0.01; %BF in energy-adjusted tertiles of dietary insulin load were 22.8 (95% CI: 21.5, 24.0), 24.5 (23.2, 25.7), 24.8 (23.6, 26.0) %, P (for trend)=0.01. Adjustment for baseline %BF attenuated these relationships (P (for trend)=0.1 and=0.08, respectively). Dietary insulin demand was not related to body mass index., Conclusion: This study suggests a prospective adverse influence of dietary insulin demand during puberty on %BF in young adulthood. Postprandial increases in insulinemia rather than increases in glycemia appear to be implicated in an unfavorable development of body composition.

Purpose of Review: In recent years, many of the concerns surrounding the glycemic index have been addressed by methodological studies and clinical trials comparing diets carefully matched for other nutrients. These findings are reviewed together with new observational evidence for the role of the dietary glycemic index in the etiology of cardiovascular disease., Recent Findings: The determination and classification of the glycemic index of a food product is now standardized by the International Standards Organization. Systematic studies using isoenergetic single and mixed meals have shown that glycemic index and/or glycemic load are stronger predictors of postprandial glycemia and insulinemia than carbohydrate content alone. In overweight individuals, a diet that combined modestly higher protein and lower glycemic index carbohydrates was the most effective diet for prevention of weight regain. New observational studies have reported increased risks of coronary heart disease associated with higher intakes of carbohydrates from high glycemic index foods. Epidemiological evidence has emerged linking dietary glycemic index to visceral fat and inflammatory disease mortality., Summary: There is growing recognition that replacing saturated fat with refined, high glycemic index carbohydrates increases postprandial glycemia and may be detrimental for weight control and predisposition to cardiovascular and inflammatory disease. In contrast, low glycemic index carbohydrates reduce risk.

The purpose of the present study was to determine the influence of the glycaemic index (GI) and glycaemic load (GL) on the ratio of tryptophan (TRP) relative to other large neutral amino acids (LNAA). Ten healthy men (age 22·9 (sd 3·4) years; BMI 23·5 (sd 1·6) kg/m2) underwent standard GI testing, and later consumed each of a mixed-macronutrient (1915 kJ; 66·5 % carbohydrate (CHO), 17 % protein and 16·5 % fat) high-GI (MHGI), an isoenergetic, mixed-macronutrient low-GI (MLGI) and a CHO-only (3212 kJ; 90 % CHO, 8 % protein, 2 % fat) high-GI (CHGI) meal on separate days. The GI, GL and insulin index values (e.g. area under the curve) were largest after the CHGI meal (117, 200, 158), followed by the MHGI (79, 59, 82) and MLGI (51, 38, 56) meals, respectively (all values were significantly different, P < 0·05). After the MHGI and MLGI meals but not after the CHGI meal, TRP was elevated at 120 and 180 min (P < 0·05). After the CHGI, LNAA was lower compared with the MLGI (P < 0·05); also the rate of decline in LNAA was higher after CHGI compared with MHGI and MLGI (both comparisons P < 0·05). The percentage increase from baseline in TRP:LNAA after CHGI (23 %) was only marginally higher than after the MHGI meal (17 %; P = 0·38), but it was threefold and nearly significantly greater than MLGI (8 %; P = 0·05). The present study demonstrates that the postprandial rise in TRP:LNAA was increased by additional CHO ingestion and higher GI. Therefore, the meal GL appears to be an important factor influencing the postprandial TRP:LNAA concentration.

Medical nutrition therapy is the first line of treatment for the prevention and management of type 2 diabetes and plays an essential part in the management of type 1 diabetes. Although traditionally advice was focused on carbohydrate quantification, it is now clear that both the amount and type of carbohydrate are important in predicting an individual's glycemic response to a meal. Diets based on carbohydrate foods that are more slowly digested, absorbed, and metabolized (i.e., low glycemic index [GI] diets) have been associated with a reduced risk of type 2 diabetes and cardiovascular disease, whereas intervention studies have shown improvements in insulin sensitivity and glycated hemoglobin concentrations in people with diabetes following a low GI diet. Research also suggests that low GI diets may assist with weight management through effects on satiety and fuel partitioning. These findings, together with the fact that there are no demonstrated negative effects of a low GI diet, suggest that the GI should be an important consideration in the dietary management and prevention of diabetes.

It has been shown that dietary glycemic index (GI) and fiber could have a role in the development of chronic diseases; however, the link between carbohydrate nutrition and development of chronic kidney disease (CKD) is unclear. We aimed to determine whether cross-sectional and longitudinal associations exist between carbohydrate nutrition (mean dietary GI, dietary intakes of carbohydrate, sugar, starch, and fiber) and CKD. Data included 2600 Blue Mountains Eye Study (1997-1999) participants aged ≥50 y. Baseline biochemistry including serum creatinine was measured. Moderate CKD was defined as estimated glomerular filtration rate (eGFR) < 60 mL·min(-1)·1.73 m(-2). Dietary data were collected in a semiquantitative FFQ. Cross-sectionally, participants in the 4th quartile of mean dietary GI intake compared with those in the first quartile (reference) had a 55% increased likelihood of having eGFR < 60 mL·min(-1)·1.73 m(-2) [multivariable-adjusted OR = 1.55 (95% CI = 1.07-2.26); P-trend = 0.01]. After multivariable adjustment, participants in the 4th quartile of dietary cereal fiber intake compared with those in the first quartile (reference) had a 50% reduced risk of incident moderate CKD (P-trend = 0.03). Higher baseline consumption of energy-dense, nutrient-poor sources of carbohydrate (e.g. cookies) yielded a 3-fold higher risk of incident CKD (P-trend = 0.01). In summary, we observed a novel link between high cereal fiber intake and reduced incidence of moderate CKD and this was supported by the cross-sectional association with dietary GI. Conversely, our data suggest that higher intake of energy-dense, nutrient-poor sources of carbohydrate, potentially through acute hyperglycemia, could impair renal function.

Objective: Insulin may play a role in prostate cancer tumorigenesis. Postprandial blood glucose and insulin responses of foods depend importantly on the carbohydrate quality and quantity, represented by glycemic index (GI), glycemic load (GL), fiber and whole-grain content, but are also influenced by intake of protein and other characteristics. The recently developed insulin index (II) quantifies the postprandial insulin secretion, also taking into account these additional characteristics., Methods: We investigated the association between dietary GI, GL, II, fiber, and whole grains and risk of total prostate cancer (n = 5,112) and subgroups of prostate cancer as defined by stage or grade in 49,934 male participants of the Health Professionals Follow-up Study. Multivariate adjusted hazard ratios (HR) and 95% confidence intervals (95% CI) were estimated using Cox proportional hazards regression., Results: Dietary GI, GL, II, or fiber was not associated with risk of total or subgroups of prostate cancer. We observed a positive association between dietary intake of whole grains and total prostate cancer (HR highest versus lowest quintile 1.13, 95% CI 1.03-1.24), which was attenuated after restriction to PSA-screened participants (HR 1.03, 95% CI 0.91-1.17)., Conclusions: These results suggest that long-term exposure to a diet with a high insulin response does not affect prostate cancer incidence.

Background: Several studies suggest that carbohydrate nutrition is related to oxidative stress and inflammatory markers., Objective: We examined whether dietary glycemic index (GI), dietary fiber, and carbohydrate-containing food groups were associated with the mortality attributable to noncardiovascular, noncancer inflammatory disease in an older Australian cohort., Design: Analysis included 1490 postmenopausal women and 1245 men aged ge 49 y at baseline (1992-1994) from a population-based cohort who completed a validated food-frequency questionnaire. Cox proportional hazards ratios were calculated both for death from diseases in which inflammation or oxidative stress was a predominant contributor and for cardiovascular mortality., Results: Over a 13-y period, 84 women and 86 men died of inflammatory diseases. Women in the highest GI tertile had a 2.9-fold increased risk of inflammatory death compared with women in the lowest GI tertile [multivariate hazard ratio in energy-adjusted tertile 3 (tertile 1 as reference): 2.89; 95% CI: 1.52, 5.51; P for trend: 0.0006, adjusted for age, smoking, diabetes, and alcohol and fiber consumption]. Increasing intakes of foods high in refined sugars or refined starches (P = 0.04) and decreasing intakes of bread and cereals (P = 0.008) or vegetables other than potatoes (P = 0.007) also independently predicted a greater risk, with subjects' GI partly explaining these associations. In men, only an increased consumption of fruit fiber (P = 0.005) and fruit (P = 0.04) conferred an independent decrease in risk of inflammatory death. No associations were observed with cardiovascular mortality., Conclusion: These data provide new epidemiologic evidence of a potentially important link between GI and inflammatory disease mortality among older women.

Weight loss can be achieved by any means of energy restriction, but the challenge is to achieve sustainable weight loss and prevent weight "creep" without increasing the risk of chronic disease. The modest success of low fat diets has prompted research on alternative dietary strategies, including high protein diets and low glycemic index (GI) diets. Conventional high carbohydrate diets, even when based on wholegrain foods, increase postprandial glycemia and insulinemia and may compromise weight control via mechanisms related to appetite stimulation, fuel partitioning, and metabolic rate. This paper makes the case for the benefits of low glycemic index diets over higher protein diets. Both strategies are associated with lower postprandial glycemia, and both are commonly labeled as "low glycemic load," but the long-term health effects are likely to be different. A large body of evidence, which now comprises observational prospective cohort studies, randomized controlled trials, and mechanistic experiments in animal models, provides robust support for low GI carbohydrate diets in the prevention of obesity, diabetes, and cardiovascular disease. Although lower carbohydrate, higher protein diets increase the rate of weight loss, cohort studies and meta-analyses of clinical trials suggest the potential for increased mortality.

Background: Low glycemic index (GI) carbohydrates have been linked to increased satiety. The drive to eat may be mediated by postprandial changes in glucose, insulin and gut peptides., Objective: To investigate the effect of a low and a high GI diet on day-long (10 h) blood concentrations of glucose, insulin, cholecystokinin (CCK) and ghrelin (GHR)., Design: Subjects (n=12) consumed a high and a low GI diet in a randomized, crossover design, consisting of four meals that were matched for macronutrients and fibre, and differed only in carbohydrate quality (GI). Blood was sampled every 30-60 min and assayed for glucose, insulin, CCK and GHR., Results: The high GI diet resulted in significantly higher glucose and insulin mean incremental areas under the curve (IAUC, P=0.027 and P=0.001 respectively). CCK concentration was 59% higher during the first 7 h of the low GI diet (394+/-95 pmol/l min) vs the high GI diet (163+/-38 pmol/l min, P=0.046), but there was no difference over 10 h (P=0.224). GHR concentration was inversely correlated with insulin concentration (Pearson correlation -0.48, P=0.007), but did not differ significantly between the low and high GI diets., Conclusions: Mixed meals of lower GI are associated with lower day-long concentrations of glucose and insulin, and higher CCK after breakfast, morning tea and lunch. This metabolic profile could mediate differences in satiety and hunger seen in some, but not all, studies.

The glycemic index (GI) of dietary carbohydrates influences glycogen storage in skeletal muscle and circulating nonesterified fatty acid (NEFA) concentrations. We hypothesized that diets differing only in GI would alter intramuscular lipid oxidation and glycogen usage in skeletal muscle and liver during subsequent exercise. Endurance-trained individuals (n = 9) cycled for 90 min at 70% Vo(2peak) and then consumed either high- or low-GI meals over the following 12 h. The following day after an overnight fast, the 90-min cycle was repeated. (1)H and (13)C magnetic resonance spectroscopy was used before and after exercise to assess intramuscular lipid and glycogen content of the vastus muscle group and liver. Blood and expired air samples were collected at 15-min intervals throughout exercise. NEFA availability was reduced during exercise in the high- compared with the low-GI trial (area under curve 44.5 +/- 6.0 vs. 38.4 +/- 7.30 mM/h, P < 0.05). Exercise elicited an approximately 55% greater reduction in intramyocellular triglyceride (IMCL) in the high- vs. low-GI trial (1.6 +/- 0.2 vs. 1.0 +/- 0.3 mmol/kg wet wt, P < 0.05). There was no difference in the exercise-induced reduction of the glycogen pool in skeletal muscle (76 +/- 8 vs. 68 +/- 5 mM) or in liver (65 +/- 8 vs. 71 +/- 4 mM) between the low- and high-GI trials, respectively. High-GI recovery diets reduce NEFA availability and increase reliance on IMCL during moderate-intensity exercise. Skeletal muscle and liver glycogen storage or usage are not affected by the GI of an acute recovery diet.

Associations between the glycemic index (GI) or glycemic load (GL) and diseases are heterogeneous in epidemiological studies. Differences in assigning GI values to food items may contribute to this inconsistency. Our objective was to address methodological issues related to the use of current GI and GL values in epidemiological studies. We performed ecological comparison and correlation studies by calculating dietary GI and GL from country-specific dietary questionnaires (DQ) from 422,837 participants from 9 countries participating in the European Prospective Investigation into Cancer and Nutrition study and single standardized 24-h dietary recalls (24-HDR) obtained from a representative sample (n = 33,404) using mainly Foster Powell's international table as a reference source. Further, 2 inter-rater and 1 inter-method comparison were conducted, comparing DQ GI values assigned by independent groups with values linked by us. The ecological correlation between DQ and 24-HDR was good for GL (overall r = 0.76; P < 0.005) and moderate for GI (r = 0.57; P < 0.05). Mean GI/GL differences between DQ and 24-HDR were significant for most centers. GL but not GI from DQ was highly correlated with total carbohydrate (r = 0.98 and 0.15, respectively; P < 0.0001) and this was higher for starch (r = 0.72; P < 0.0001) than for sugars (r = 0.36; P < 0.0001). The inter-rater and inter-method variations were considerable for GI (weighted kappa coefficients of 0.49 and 0.65 for inter-rater and 0.25 for inter-method variation, respectively) but only mild for GL (weighted kappa coefficients > 0.80). A more consistent methodology to attribute GI values to foods and validated DQ is needed to derive meaningful GI/GL estimates for nutritional epidemiology.

Hyperglycemia and insulin resistance are independent risk factors for cardiovascular disease (CVD). Postprandial glycemic "spikes" adversely affect vascular structure and function via multiple mechanisms including oxidative stress, inflammation, low-density lipoprotein oxidation, protein glycation, and procoagulant activity. Glycemic responses can be reliably predicted by considering both the quantity and quality of carbohydrate. The glycemic index (GI), a measure of carbohydrate quality, has provided insights that knowledge of the sugar or starch content has not. In prospective observational studies, dietary GI and/or glycemic load (GL; the product of the amount of carbohydrate and GI) independently predict CVD, with relative risk ratios of 1.2 to 1.9 comparing highest and lowest quartiles. In randomized controlled trials in overweight subjects, diets based on low GI carbohydrates have decreased plasminogen activator inhibitor-1 activity and other CVD risk factors over and above that of conventional low-fat diets. Taken together, the findings suggest that clinicians may be able to improve CVD outcomes by recommending the judicious use of low GI/GL foods.

Background and Purpose: It is unclear whether diets with high glycemic index (GI) and low cereal fiber (CF) are associated with greater risk of stroke. We aimed to assess the relationship between dietary GI and CF content, retinal microvasculature changes, and stroke-related mortality., Methods: The study consisted of a population-based cohort, 49+ years, examined at baseline (1992 to 1994). At baseline, participants completed validated food frequency questionnaires. Mean GI was calculated using an Australian database. Retinal arteriolar and venular diameters were measured from photographs. Mortality data were derived using the Australian National Death Index., Results: Over 13 years, 95 of 2897 participants (3.5%) died from stroke. Increasing GI (hazard ratio, 1.91; 95% CI, 1.01 to 3.47, highest versus lowest tertile) and decreasing CF (hazard ratio, 2.13; 95% CI, 1.19 to 3.80, lowest versus highest tertile) predicted greater risk of stroke death adjusting for multiple stroke risk factors. Persons consuming food in the highest GI tertile and lowest CF tertile had a 5-fold increased risk of stroke death (hazard ratio, 5.06; 95% CI, 1.67 to 15.22). Increasing GI and decreasing CF were also associated with retinal venular caliber widening (P(trend)<0.01). Adjustment for retinal venular caliber attenuated stroke death risk associated with high GI by 50% but did not affect the risk associated with low CF consumption., Conclusions: High-GI and low-CF diets predict greater stroke mortality and wider retinal venular caliber. The association between a high-GI diet and stroke death was partly explained by GI effects on retinal venular caliber, suggesting that a high-GI diet may produce deleterious anatomic changes in the microvasculature.

Background: Dietary factors are known risk factors for age-related macular degeneration (AMD) -- the leading cause of visual loss among persons aged > or =65 y. High-glycemic-index diets have been hypothesized as a risk factor for AMD, but prospective data are unavailable., Objective: The objective was to examine the association between dietary glycemic index and the 10-y incidence of AMD in the Blue Mountain Eye Study population., Design: This was a population-based cohort study with 3,654 participants (> or =49 y) examined at baseline (1992-1994); 2,335 patients were reexamined after 5 y and 1952 after 10 y. The Wisconsin System was used to grade 10-y incident early and late AMD from retinal photographs. A food-frequency questionnaire was used to collect dietary information at baseline, and an Australian database was used to calculate the mean glycemic index., Results: Over 10 y, 208 of 1,810 persons (cumulative incidence: 14.1%) developed early AMD. After age, smoking, other risk factors, and dietary constituents were adjusted for, a higher mean dietary glycemic index was associated with an increased 10-y risk of early AMD in a comparison of quartiles 1 and 4 [relative risk (RR): 1.77; 95% CI: 1.13, 2.78; P for trend = 0.03]. Conversely, a greater consumption of cereal fiber (RR: 0.68; 95% CI: 0.44, 1.04; P for trend = 0.05) and breads and cereals (predominantly lower glycemic index foods such as oatmeal) (RR: 0.67; 95% CI: 0.44, 1.02; P for trend = 0.03) was associated with a reduced risk of incident early AMD. No relation was observed with late AMD., Conclusions: A high-glycemic-index diet is a risk factor for early AMD -- the recognized precursor of sight-threatening late AMD. Low-glycemic-index foods such as oatmeal may protect against early AMD.

Background: High-glycemic index diets have been linked to greater risk of cardiovascular disease and type 2 diabetes. Postprandial glycemia within the normal range may promote oxidative stress and inflammatory processes underlying the development of disease., Objective: We explored acute differences in the activation of the inflammatory marker nuclear factor-kappaB after consumption of 2 carbohydrate meals matched for macronutrient and micronutrient composition but differing in glycemic index., Design: After an overnight fast, 10 young, lean healthy subjects were fed in random order 3 meals providing 50 g of available carbohydrate as glucose, white bread, or pasta. Venous blood samples were collected at 0, 1, 2, and 3 h, and nuclear proteins were extracted from mononuclear cells. Changes in nuclear factor-kappaB-p65 proteins were detected by Western blotting. Acute changes in other markers of oxidative stress (nitrotyrosine and soluble intercellular adhesion molecule-1) were also assessed., Results: The maximum increase in nuclear factor-kappaB activation was similar after the bread meal [mean (+/-SEM) area under the curve: 69 +/- 16% optical density x h] and the glucose challenge (75 +/- 9% optical density x h), but was 3 times higher than after the pasta meal (23 +/- 5% optical density x h) (P < 0.05). Similarly, changes in nitrotyrosine, but not soluble intercellular adhesion molecule-1, were higher after glucose and bread than after pasta (P = 0.01 at 2 h)., Conclusions: The findings suggest that high-normal physiologic increases in blood glucose after meals aggravate inflammatory processes in lean, young adults. This mechanism may help to explain relations between carbohydrates, glycemic index, and the risk of chronic disease.

Intramyocellular lipid (IMCL) and plasma NEFA are important skeletal muscle fuel sources. By raising blood insulin concentrations, carbohydrate ingestion inhibits lypolysis and reduces circulating NEFA. We hypothesised that differences in the postprandial glycaemic and insulin response to carbohydrates (i.e. glycaemic index; GI) could alter NEFA availability and IMCL use during subsequent exercise. Endurance-trained individuals (n 7) cycled for 90 min at 70 % V O2peak and then consumed either high GI (HGI) or low GI (LGI) meals over the following 12 h. The following day after an overnight fast, the 90 min cycle was repeated. IMCL content of the vastus lateralis was quantified using magnetic resonance spectroscopy before and after exercise. Blood samples were collected at 15 min intervals throughout exercise and analysed for NEFA, glycerol, glucose, insulin, and lactate. Substrate oxidation was calculated from expired air samples. The 90 min cycle resulted in >2-fold greater reduction in IMCL in the HGI trial (3.5 (sem 1.0) mm/kg wet weight) than the LGI trial (1.6 (sem 0.3) mm/kg wet weight, P < 0.05). During exercise, NEFA availability was reduced in the HGI trial compared to the LGI trial (area under curve 2.36 (sem 0.14) mEq/l per h v. 3.14 (sem 0.28) mEq/l per h, P < 0.05 respectively). No other differences were significant. The findings suggest that HGI carbohydrates reduce NEFA availability during exercise and increase reliance on IMCL as a substrate source during moderate intensity exercise.

Weight loss can be achieved by any means of energy restriction, but the challenge is to achieve sustainable weight loss and prevent weight 'creep' without increasing the risk of chronic disease. The modest success of low fat diets has prompted research on alternative dietary strategies including high protein diets and low glycemic index (GI) diets. Conventional high carbohydrate diets, even when based on whole grain foods, increase postprandial glycaemia and insulinemia and may compromise weight control via mechanisms relating to appetite stimulation, fuel partitioning and metabolic rate. This paper makes the case for the benefits of low glycemic index diets over higher protein diets. Both strategies are associated with lower postprandial glycemia and both are commonly labelled as 'low glycemic load' but the long-term health effects are likely to be different. There is now a large body of evidence comprising observational prospective cohort studies, randomised controlled trials and mechanistic experiments in animal models, that provides robust support for low GI carbohydrate diets in the prevention of obesity, diabetes and cardiovascular disease. While lower carbohydrate, higher protein diets also increase the rate of weight loss, cohort studies and meta-analyses of clinical trials suggest the potential for increased mortality.

Postprandial hyperglycemia is increasingly recognized as an independent risk factor for cardiovascular disease. Glycemic "spikes" may adversely affect vascular structure and function via multiple mechanisms, including (acutely and/or chronically) oxidative stress, inflammation, low-density lipoprotein oxidation, protein glycation, and procoagulant activity. Postprandial glycemia can be reliably predicted by considering both the amount and type of carbohydrate. In particular, the glycemic index (GI), a measure of postprandial glycemic potency weight for weight of carbohydrate, has provided insights that knowledge of the sugar or starch content has not. In prospective observational studies, dietary GI and/or glycemic load independently predict cardiovascular disease, with relative risk ratios of 1.2 to 1.7 comparing highest and lowest quintiles. In randomized controlled trials in overweight subjects, diets based on low-GI carbohydrates have produced better cardiovascular-related outcomes than conventional low-fat diets. Taken together, the findings suggest that health professionals may be able to improve cardiovascular outcomes by recommending the judicious use of low- GI/glycemic load foods.

Background: Although dietary carbohydrates are thought to play a role in cataractogenesis, few epidemiologic studies have examined links between carbohydrate nutrition and cataract., Objectives: We investigated the associations between dietary glycemic index (GI), glycemic load (GL), total carbohydrate intake, and 10-y incident nuclear, cortical, and posterior subcapsular cataract., Design: Of 3654 baseline participants in an Australian population aged >/=49 y (1992-1994), 933 were seen after 5 and/or 10 y, had completed a detailed semiquantitative food-frequency questionnaire, had no previous cataract surgery or baseline cataract, and had photographs taken to assess incident cataract with the Wisconsin Cataract Grading System. Dietary information was collected with a validated food questionnaire. GI was calculated from a customized database of Australian foods. GI, GL, and all other nutrients were energy adjusted. Hazard ratios (HRs) and 95% CIs were calculated with the use of discrete logistic models., Results: After age, sex, diabetes, and other factors were controlled for, each SD increase in GI significantly predicted incident cortical cataract (HR: 1.19; 95% CI: 1.01, 1.39). Participants within the highest compared with the lowest quartile of GI were more likely to develop incident cortical cataract (HR: 1.77; 95% CI: 1.13, 2.78; P for trend = 0.035). These findings were similar after excluding participants with diabetes, although they were slightly attenuated and marginally nonsignificant (HR: 1.16; 95% CI: 0.98, 1.37, per SD increase in GI). No association was found between GI and nuclear or posterior subcapsular cataract and between GL or carbohydrate quantity and any cataract subtype., Conclusion: In an Australian cohort, poorer dietary carbohydrate quality, reflected by high GI, predicted incident cortical cataract.

Purpose of Review: Several lines of evidence indicate that exaggerated postprandial glycemia puts individuals without diabetes at greater risk of developing cardiovascular disease. In large, prospective observational studies, including meta-analyses, higher 120 min post-load blood glucose and glycated hemoglobin (a measure of average blood glucose level over time) independently predict cardiovascular mortality and morbidity in individuals without diabetes. These findings imply that the glycemic nature of dietary carbohydrates may also be relevant. We aim to provide a clearer perspective on how the glycemic impact of carbohydrates may modulate development of cardiovascular disease., Recent Findings: In ecological studies, average dietary glycemic index (a measure of the postprandial glycemic potential of carbohydrates) and glycemic load (average glycemic index x amount of carbohydrate) predicts coronary infarct and cardiovascular disease risk factors, including HDL cholesterol, triglycerides and C-reactive protein. In short-term intervention studies of overweight and hyperlipidemic patients, low glycemic index diets lead to improvements in cardiovascular disease risk factors, including reduced LDL cholesterol and improved insulin sensitivity, as well as greater body fat loss on energy-restricted diets. Molecular studies indicate that physiological hyperglycemia induces overproduction of superoxide by the mitochondrial electron-transport chain, resulting in inflammatory responses and endothelial dysfunction., Summary: Taken together, the findings suggest that conventional high-carbohydrate diets with their high glycemic index may be suboptimal, particularly in insulin-resistant individuals. Because around one in four adults has impairments in postprandial glucose regulation, the glycemic potential of carbohydrates warrants further investigation in cardiovascular disease prevention.

Dietary glycemic load, the mathematical product of the glycemic index (GI) of a food and its carbohydrate content, has been proposed as an indicator of the glucose response and insulin demand induced by a serving of food. To validate this concept in vivo, we tested the hypotheses that 1). portions of different foods with the same glycemic load produce similar glycemic responses; and 2). stepwise increases in glycemic load for a range of foods produce proportional increases in glycemia and insulinemia. In the first study, 10 healthy subjects consumed 10 different foods in random order in amounts calculated to have the same glycemic load as one slice of white bread. Capillary blood samples were taken at regular intervals over the next 2 h. The glycemic response as determined by area under the curve was not different from that of white bread for nine foods. However, lentils produced lower than predicted responses (P < 0.05). In the second study, another group of subjects was tested to determine the effects of increasing glycemic load using a balanced 5 x 5 Greco-Latin square design balanced for four variables: subject, dose, food and order. Two sets of five foods were consumed at five different glycemic loads (doses) equivalent to one, two, three, four and six slices of bread. Stepwise increases in glycemic load produced significant and predictable increases in both glycemia (P < 0.001) and insulinemia (P < 0.001). These findings support the concept of dietary glycemic load as a measure of overall glycemic response and insulin demand.

Objective: Practical use of the glycaemic index (GI), as recommended by the FAO/WHO, requires an evaluation of the recommended method. Our purpose was to determine the magnitude and sources of variation of the GI values obtained by experienced investigators in different international centres., Design: GI values of four centrally provided foods (instant potato, rice, spaghetti and barley) and locally obtained white bread were determined in 8-12 subjects in each of seven centres using the method recommended by FAO/WHO. Data analysis was performed centrally., Setting: University departments of nutrition., Subjects: Healthy subjects (28 male, 40 female) were studied., Results: The GI values of the five foods did not vary significantly in different centres nor was there a significant centrexfood interaction. Within-subject variation from two centres using venous blood was twice that from five centres using capillary blood. The s.d. of centre mean GI values was reduced from 10.6 (range 6.8-12.8) to 9.0 (range 4.8-12.6) by excluding venous blood data. GI values were not significantly related to differences in method of glucose measurement or subject characteristics (age, sex, BMI, ethnicity or absolute glycaemic response). GI values for locally obtained bread were no more variable than those for centrally provided foods., Conclusions: The GI values of foods are more precisely determined using capillary than venous blood sampling, with mean between-laboratory s.d. of approximately 9.0. Finding ways to reduce within-subject variation of glycaemic responses may be the most effective strategy to improve the precision of measurement of GI values.

Australian Aboriginal and Torres Strait Islander peoples are disproportionately affected by diet-related disease such as type 2 diabetes, the rate of which is 20 fold higher than that of non-Indigenous young Australians(1). Before colonisation, Gomeroi and other First Nations people harvested, threshed and ground native grass seeds with water into a paste before cooking(2). The introduction of white refined flour has meant that time-consuming grass seed processing has mainly ceased, and native grains are no longer eaten habitually. The aim of this study was to determine the effect of 10% incorporation of two native grain flours on postprandial blood glucose response and Glycemic Index (GI). Five male and five female subjects, with a mean age of 30 ± 0.9 and BMI of 21.6 ± 0.4 and normoglycemic, participated in GI testing of three flour + water pancake compositions matched for available carbohydrate: 100% wheat (Wheat) and 90% wheat:10% native grains (Native_ a and Native_ b). Effect on satiety was determined using subjective ratings of hunger/fullness over the time course of the GI testing. In comparison to the plain flour pancake, replacing 10% plain wheat flour with Native_ b flour significantly reduced the GI by 28.8% from 73 ± 5 to 48 ± 5, having a profound effect on postprandial blood glucose levels in 9 of 10 subjects (p<0.05, paired t-test). The GI of 10% Native_ a flour pancake was not different from 100% wheat flour pancake (75 ± 5). Satiety tended to be greater when native grains were incorporated but this study was not powered to detect effect on satiety. In conclusion, replacing only 10% of plain wheat flour with Native_ b flour was sufficient to significantly reduce the blood glycemic response to the pancake. This replacement could be easily implemented for prevention and treatment of type 2 diabetes. For Aboriginal people with access to grain Country, the nutritional health benefits associated with eating native grains, as well as the cultural benefits of caring for Country, will have a direct transformational impact on local communities. Our vision is to revitalise Gomeroi grains and to guide a sustainable Indigenous-led industry to heal Country and people through co-designed research. [ABSTRACT FROM AUTHOR]

Low-fat diets produce spontaneous weight loss in the research setting, but as a public health strategy, they have been disappointing. Insulin resistance and impairments in insulin secretory function leading to postprandial hyperglycaemia are now common, making the current context greatly different to that of 25 years ago. There is increasing evidence that reducing the proportion of energy derived from carbohydrate or reducing the glycaemic index (GI) of the carbohydrate improves the rate of fat loss and cardiovascular risk factors. The proposed mechanisms include higher satiety, higher metabolic rate, reduced postprandial glycaemia and/or insulinaemia and higher fat oxidation. Although dietary glycaemic load can be reduced either by lowering the GI of the carbohydrate or by reducing carbohydrate energy, the metabolic and physiological consequences are not the same. Exchanging high for low-GI foods, without changing the macronutrient ratio, may be optimal because it is simple, cost-effective and often associated with higher intake of whole grains and greater food volume, and factors that maximize the chance of sustained weight loss. Healthy low-GI diets allow for moderate intakes of sugars, including sweetened dairy foods, fruits and confectionery items, and can be easily adapted for individuals of different ethnicities, vegetarians and low-income groups.International Journal of Obesity (2006) 30, S40–S46. doi:10.1038/sj.ijo.0803491 [ABSTRACT FROM AUTHOR]

In rats, prolonged feeding of high glycemic index (GI) starch results in basal hyperinsulinemia and an elevated insulin response to an intravenous glucose tolerance test (IVGTT). The aim of this study was to assess hepatic and peripheral insulin resistance (IR) using euglycemic hyperinsulinemic clamps. Insulin sensitivity, epididymal fat deposition and fasting leptin concentrations were compared in rats fed isocalorically a low or high GI diet for 7 wk (45% carbohydrate, 35% fat and 20% protein as energy) or a high fat diet (20% carbohydrate, 59% fat and 21% protein as energy) for 4 wk so that final body weights were similar. At the end of the study, high GI rats had higher basal leptin concentration and epididymal fat mass than the low GI group, despite comparable body weights. High GI and high fat feeding both resulted in the higher insulin response during IVGTT, but impaired glucose tolerance was seen only in rats fed high fat. The GI of the diet did not affect basal and clamp glucose uptake or hepatic glucose output, but high fat feeding induced both peripheral and hepatic IR. The findings suggest that hypersecretion of insulin without IR may be one mechanism for increased fat deposition in rats fed high GI diets. [ABSTRACT FROM AUTHOR]

Presents information from a study that determined the impact of variety, cooking method, and maturity on the glycaemic index of potatoes. Materials and methods; Results and discussion; Conclusions.

In cardiovascular disease, dietary fat and blood lipids have attracted the lion's share of attention. But carbohydrate, the macronutrient that increases when fats are restricted, may not be the totally desirable nutrient that we believe. The findings of the Lyon Heart Study, one of the most important nutrition studies ever carried out, emphasise that the 'prudent' high carbohydrate western diet is not the best choice for reducing cardiovascular events. One explanation is the potential to increase postprandial hyperglycemia, an under-recognised risk factor for cardiovascular and total mortality in the non-diabetic population. In the DECODE study and a host of other large prospective cohort studies, high postchallenge blood glucose was associated with 1.8 to 3 times greater relative risk of death. The glycemic potential of carbohydrates is therefore relevant to both prevention and management of coronary disease. Diets based on high glycemic index (GI) carbohydrate foods have been shown to 1) increase day-long blood glucose and insulin levels 2) exacerbate insulin resistance in predisposed individuals 3) adversely affect markers of the metabolic syndrome (triglycerides and HDL-cholesterol) in intervention studies and 4) increase the risk of coronary disease in a healthy population. How does high blood glucose increase the risk of CVD? Laboratory studies have shown that high glucose levels even within the normal range adversely affect endothelial function via a multitude of mechanisms including oxidative stress, inflammatory factors, protein glycation, LDL oxidation, pro-coagulatory and anti-fibrinolytic activity. In intervention studies of men with hyperlipidemia, Jenkins et al showed that a low GI diet was associated with lower TG and LDL cholesterol levels compared with an otherwise equivalent diet based on high GI carbohydrates. In women with a family history of CVD following a low GI diet for 4 weeks, Frost et al found increased insulin sensitivity after a glucose challenge and increased glucose uptake in isolated adipocytes. Even in lean young adults, a low GI diet reduced muscle triglycerides, a marker of insulin resistance, despite no effect on insulin-stimulated glucose uptake. Epidemiological studies provide further support. In the Nurses Health Study, those in the highest quintile of GI and glycemic load (GI x carbohydrate) had nearly double the relative risk of coronary infarct, compared to those in the lowest quintile, after adjustment for known risk factors, including fibre. In several observational studies of healthy men and women, high GI diets have been consistently associated with lower HDL levels. In post-menopausal women, high GI diets were associated with higher C-reactive protein levels (a marker of low grade chronic inflammation), high triglycerides and lower HDL levels, all of which increase the risk of CVD. Low GI diets may also reduce visceral fat deposition. In recent studies, we compared 4 weight loss diets of differing glycemic load (GL). Compared to the conventional low fat diet with a high GL, the reduced GL diets produced greater rates of weight loss but only the low GI diet was associated with significant reductions in LDL-cholesterol (unpublished data). Finally, the STOP-NIDDM study using Acarbose (a drug which slows brush border digestion of carbohydrates) provides direct evidence that reducing the rate of carbohydrate absorption per se halves the risk of cardiovascular events and hypertension. The use of naturally-occurring 'slow-release' or low glycemic index (GI) carbohydrates to achieve the same end remains controversial. [ABSTRACT FROM AUTHOR]

Objective: To investigate the relationship between glycemic index (GI), glycemic load (GL) and diabetes in a sample of older Australians. Design: 3654 people aged 49 years or older, representing 88% of permanent residents in the two postcode areas west of Sydney, underwent a detailed medical examination. The medical examination included a history of diabetes and associated risk factors. Fasting pathology tests, including plasma glucose, were obtained for 88% of the 3654 residents, and a 145-item semiquantitative food frequency questionnaire (FFQ) was completed by 89% of the residents. Outcomes: A history of diabetes was reported by 218 people (6%), including 111 (7%) men and 107 (5.2%) women. Another 66 (2.2%) people had a FBG ≥ 7.0 mM, indicating they had undiagnosed Type 2 diabetes. Therefore a total of 8.2% of people had diabetes, which is slightly higher than the estimate for Australian adults determined by the AusDiab study (7.5%). In addition to this, 127 (4.2%) people had impaired fasting glycaemia. The mean (±SD) GI and GL was calculated from the FFQ's and determined to be 56.5 (4.2) and 133 (45.8) units respectively. Valid food frequency data was available for 164 people with diabetes. People with diabetes had significantly lower mean GI (55.4±5.05 vs 56.34±4.16, P=0.007) and GL (118.4±41.15 vs 133.98±45.91, P<0.0001) than people who did not have diabetes. Conclusion: People with diabetes living in Australia choose a diet with a significantly lower average GI and GL than Australians who do not have diabetes. [ABSTRACT FROM AUTHOR]

Background -- Compared with conventional low fat diets, high-protein and low-glycemic index (GI) diets have been associated with greater rate of weight loss. While both methods reduce dietary glycemic load (GL), the effects on cardiovascular risk may differ. Objective -- To evaluate the effects of 4 diets varying in GL, GI and protein on lipid and glucose metabolism. Design -- A 12-week randomised trial of 4 ad libitum diets: diet 1 was a high carbohydrate, high GI diet (HGI), diet 2 was similarly high in carbohydrate but low GI (LGI), diets 3 and 4 replaced some of the carbohydrate with protein, specifically from lean red meat, and included carbohydrate from either high or low GI foods (HP/HGI and HP/LGI respectively). The diets were similar in fat (30% energy) and type of fat. All key foods and some pre-prepared meals were provided on a weekly basis to assist compliance. Fasting blood samples were taken 0, 6 and 13 weeks. Outcomes -- In total, 129 subjects were recruited and 116 completed the intervention. Changes in weight and body composition were reported previously. In the primary intention-to-treat analysis, total cholesterol and LDL-cholesterol changes showed significant differences among the 4 diets (P = 0.04 and 0.019 respectively). Despite similar weight loss, total and LDL-cholesterol rose by +5% and +8% respectively on the HP/HGI diet and fell by -4% and -6% respectively on the LGI diet (p = 0.033 and 0.013 for total and LDL-cholesterol respectively). Overall, there was a significant effect of GI, but not protein content, on change in total cholesterol (P = 0.019) and LDL cholesterol (P = 0.009). HDL-cholesterol rose and triglyceride concentrations fell in all groups with no differences among the four diets. Conclusions -- Reduced GL diets have varying effects on cardiovascular risk factors. Low GI carbohydrate foods may be more important in high protein diets because of their capacity to attenuate undesirable changes in lipid metabolism. [ABSTRACT FROM AUTHOR]