***TASK*** the task is to summarize an input biomedical literature in six sentences 
    ***INPUT*** the input is a biomedical literature 
    ***OUTPUT*** the output is the summary of an input biomedical literature in six sentences 
    ***DOCUMENTATION*** 
    ***EXAMPLES*** 
    Input: The macronutrient composition of a breakfast that could facilitate performance after an overnight fast remains unclear . As glucose is the brain 's major energy source , the interest is in investigating meals differing in their blood glucose-raising potential . Findings vary due to unaccounted differences in glucoregulation , arousal and cortisol secretion . We investigated the effects of meals differing in glycaemic index ( GI ) and glycaemic load ( GL ) on cognition and mood in school children . A total of seventy-four school children were matched and r and omly allocated either to the  high-GL or low-GL  group . Within each GL group , children received high-GI and low-GI breakfasts .  Cognitive function ( CF ) and mood were measured 95 - 140 min after breakfast . Blood glucose and salivary cortisol were measured at baseline , before and after the CF tests . Repeated- measures ANOVA was used to identify differences in CF , mood , glucose and cortisol levels between the breakfasts . Low-GI meals predicted feeling more alert and happy , and less nervous and thirsty ( P < 0·05 for each ) ; high-GL meals predicted feeling more confident , and less sluggish , hungry and thirsty ( P < 0·05 for each ) . High-GL ( P < 0·001 ) and high-GI ( P = 0·05 ) meals increased glucose levels 90 min after breakfast , and high-GI meals increased cortisol levels ( P < 0·01 ) . When baseline mood , glucose and cortisol levels were considered , low-GI meals predicted better declarative-verbal memory ( P = 0·03 ) , and high-GI meals better vigilance ( P < 0·03 ) ; observed GI effects were valid across GL groups . GI effects on cognition appear to be domain specific . On balance , it would appear that the low-GI high-GL breakfast may help to improve learning , and of potential value in informing government education policies relating to dietary recommendations and implementation concerning breakfast Background / Objectives : Considering the importance of glucose as a brain substrate , the postpr and ial rate of glucose delivery to the blood could be expected to affect cognitive functions . The purpose was to evaluate to what extent the rate of glucose absorption affected measures of cognitive performance in the postpr and ial period . In addition , cognitive performance was evaluated in relation to individual glucoregulation . Subjects/ Methods : A white wheat bread ( WWB ) enriched with guar gum ( G-WWB ) with the capacity to produce a low but sustained blood glucose net increment was developed . The G-WWB was evaluated in the postpr and ial period after breakfast with respect to effects on cognitive function ( working memory and selective attention ( SA ) ) in 40 healthy adults ( 49–71 years , body mass index 20–29 kg/m2 ) , using a high glycaemic index WWB for comparison in a r and omised crossover design . Results : The G-WWB improved outcome in the cognitive tests ( SA test ) in the later postpr and ial period ( 75–225 min ) in comparison with the WWB ( P<0.01 ) . Subjects with better glucoregulation performed superior in cognitive tests compared with subjects with worse glucoregulation ( P<0.05 ) . Conclusions : Beneficial effects on cognitive performance were observed with the G-WWB in the late postpr and ial period . The positive effect is suggested to emanate from improved insulin sensitivity , possibly in a combination with an enhanced neural energy supply . The results highlight the importance of carbohydrate foods that induces a low but sustained blood glucose profile in enhancing postpr and ial cognitive functions Background / Objectives : The effect of Glycaemic Index ( GI ) and Load ( GL ) of breakfasts on satiety and aspects of cognitive function in children is inconclusive . We aim ed to assess if isocaloric breakfasts differing in GL ( by replacing high-GI carbohydrate foods with dairy protein foods ) acutely alter cognitive function and satiety in 10- to 12-year-old children . Subjects/ Methods : A total of 39 children , aged 11.6±0.7 years with body mass index 18.9±3.0 kg/m2 ( Mean±s.e . ) participated in a r and omised crossover trial of three isocaloric breakfasts ( 1.3 MJ ) : high GL ( HGL : 7 g protein , 9 g fat , 50 g carbohydrate , GL 33 ) ; medium GL ( MGL : 14 g protein , 9 g fat , 45 g carbohydrate , GL 24 ) and low GL ( LGL : 18 g protein , 10 g fat , 38 g carbohydrate , GL 18 ) . Blood glucose was recorded using a continuous glucose monitor . Subjective hunger and cognitive performance were measured before and hourly after consuming the test breakfast via a computer-delivered battery . Ad libitum intake at a buffet lunch meal was measured at 3 h at the end of testing . Results : Incremental area under the glucose curve ( iAUC ) was significantly different with HGL > MGL > LGL ( P<0.001 ) . Glucose concentrations fell below baseline after 83±6 min for HGL , 63±5 min ( MGL ) and 67±5 min (LGL)(P=0.009 ) . Breakfast GL did not significantly alter changes in cognitive function or self-reported satiety throughout testing . Energy intake at lunch was not significantly different between treatments ( HGL 2943±168 kJ ; MGL 2949±166 kJ ; LGL 2993±191 kJ ) . Conclusions : Reducing breakfast GL by replacing carbohydrate with protein does not alter satiety or cognition over 3 h in 10- to 12-year-old children OBJECTIVE . Breakfast-eating frequency declines through adolescence and has been inversely associated with body weight in cross-sectional studies , with few prospect i ve studies on this topic . This study was conducted to examine the association between breakfast frequency and 5-year body weight change in 2216 adolescents . PATIENTS AND METHODS . Project EAT ( Eating Among Teens ) was a 5-year longitudinal study of eating patterns and weight concerns among adolescents .  Surveys were completed in 1998–1999 ( time 1 ) and 2003–2004 ( time 2 ) . Multivariable linear regression was used to examine the association between breakfast frequency and change in BMI , with adjustment for age , socioeconomic status , race , physical activity , time 1 BMI and breakfast category , and time 1 dietary and weight-related variables . RESULTS . At time 1 , frequency of breakfast was directly associated with intake of carbohydrate and fiber , socioeconomic status , white race , and physical activity and inversely associated with smoking and alcohol consumption and dieting and weight-control behaviors . In cross-sectional analyses at times 1 and 2 , inverse associations between breakfast frequency and BMI remained largely independent of all of the confounding and dietary factors . Weight-related factors ( concerns , behaviors , and pressures ) explained little of the breakfast- BMI association . In prospect i ve analyses , frequency of breakfast was inversely associated with BMI in a dose-response manner . Further adjustment for confounding and dietary factors did not seem to explain the association , but adjustment for weight-related variables seemed to partly explain this finding . CONCLUSIONS . Although experimental studies are needed to verify whether the association between breakfast and body weight is of a causal nature , our findings support the importance of promoting regular breakfast consumption among adolescents . Future studies should further examine the role of breakfast habits among youth who are particularly concerned about their weight In order to examine the effect of energy intake at breakfast on school performance the same morning , the parents of ten parallel school classes of 10-year-old school children at five different schools were persuaded to alter their child 's breakfast regimen at home over a period of 4 successive days . A total of 195 families were provided with st and ard breakfasts with either low or high energy content . Uneaten food was returned and weighed . Individual children were r and omly assigned to breakfast alternative on any given day . The teachers who carried out the performance assessment s at school were blind to treatment condition . Voluntary physical endurance and the performance of a creativity test were significantly better after a breakfast from which children derived over 20 % of their recommended daily energy intake than after a breakfast from which they obtained less than 10 % of recommended values . The error rate in an addition task was negatively correlated and the rate of working in a number checking task was positively correlated with individual energy intake from the low-energy breakfast . Significantly fewer children reported feeling bad and self-estimates of hunger sensation were lower during the morning at school after the high energy breakfast . Estimates of energy intake at breakfast based on 24-h dietary recall interviews with the children carried out by telephone at their homes showed good correlation with estimates based on returned food ( r = 0.89 ) . Energy intake at breakfast as estimated from returned food had no significant effect on energy intake at school lunch as estimated by dietary recall Rationale . Glucose is the main metabolic fuel of the brain . The rate of glucose delivery from food to the bloodstream depends on the nature of carbohydrates in the diet , which can be summarized as the glycaemic index ( GI ) . Objectives . To assess the benefit of a low versus high GI breakfast on cognitive performances within the following 4 h. Methods . The influence of the GI of the breakfast on verbal memory of young adults was measured throughout the morning in parallel to the assessment of blood glucose levels . The learning abilities of rats performing an operant-conditioning test 3 h after a breakfast-like meal of various GI was also examined . Results . A low GI rather than high GI diet improved memory in humans , especially in the late morning ( 150 and 210 min after breakfast ) . Similarly , rats displayed better learning performance 180 min after they were fed with a low rather than high GI diet . Conclusion . Although performances appeared to be only remotely related to blood glucose , our data provide evidence that a low GI breakfast allows better cognitive performances later in the morning 
    Output:
    
However , whereas the hypothesis of a better and more sustained performance with a breakfast providing > 20 % daily energy intake still needs substantiation , there does appear to be emerging , but still equivocal , evidence that a lower postpr and ial glycemic response is beneficial to cognitive performance