79 A review in adults concluded that there is now a large body of evidence providing robust support for LGI diets in the prevention of obesity, diabetes and cardiovascular disease.27 Although, relative to adults,

a small number of interventions have assessed the impact of dietary GI on health markers in young people. The MDV3100 clinical trial available evidence indicates reduced GI diets have implications for lowering BMI, metabolic syndrome and cardiovascular risk factors, hyperglycaemia, fasted glucose and insulin and hunger.28, 29 and 80 Moreover, a reduced-GL diet may be more effective at improving BMI and insulin sensitivity compared with a reduced-fat diet.81 However, it should be noted that some

have reported dietary GI may not influence health markers in children.82 Encouragingly, health benefits of reducing dietary GI may be achieved by targeting Cabozantinib mouse just the breakfast meal in adults,83 although these effects have yet to be investigated in young people. Potential health-enhancing effects of reduced GI diets in young people are, therefore, encouraging, but require greater research attention. Evidence on the effect of manipulating habitual GI at the breakfast meal only (rather than the diet as a whole) in young people would be valuable; cross-sectional and prospective associations between breakfast GI, BMI, and health markers should be explored. Plausible mechanisms explaining relationships between dietary GI and

health may arise from the contrasting acute metabolic responses to HGI and LGI foods. Indeed, much of the support for the promotion of LGI breakfasts comes from experimental studies investigating the acute effect of HGI and LGI breakfasts on metabolism and satiety. In young people, the effect of manipulations in breakfast GI on glucose, insulin, satiety, and fat oxidation have been investigated; the following section reviews this evidence and draws on the more extensive adult literature where appropriate. Numerous studies in adults have shown that Carnitine palmitoyltransferase II LGI compared with HGI mixed-breakfast meals reduce postprandial glycaemia and insulinaemia27, 84 and 85 and studies in young people have provided similar findings.86 and 87 In adults, LGI CHO consumption may also attenuate glycaemic and insulinaemic responses to standard subsequent meals due to the “second meal effect”,88 although similar evidence in young people appears to be unavailable. Reduced blood glucose decreases the quantity of insulin required to clear glucose from the blood, which may up-regulate insulin receptors on cells and increase insulin sensitivity.89 Recent findings in young people indicate that the higher glycaemic response to HGI compared with LGI breakfast consumption was exaggerated in overweight compared with non-overweight girls.