***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: BACKGROUND Short-term high-carbohydrate ( HC ) diets induce metabolic alterations , including hypertriacylglycerolemia , in both the fasting and postpr and ial states . The underlying tissue-specific alterations in fatty acid metabolism are not well understood . OBJECTIVE We investigated alterations in exogenous and endogenous fatty acid metabolism by using stable isotope tracers to label meal triacylglycerol and plasma fatty acids . DESIGN Eight healthy subjects consumed isocaloric diets containing a high percentage of energy from carbohydrates or a higher percentage of energy from fat for 3 d in a r and omized crossover dietary intervention study . A test meal containing [ U-13C ] palmitate was combined with intravenous infusion of [ 2H2 ] palmitate to label plasma fatty acids and VLDL triacylglycerol . Blood and breath sample s were taken before the meal and for 6 h postpr and ially . Blood sample s were drawn from the femoral artery and from veins draining subcutaneous adipose tissue and forearm muscle for monitoring of tissue-specific metabolic substrate partitioning . RESULTS Systemic triacylglycerol concentrations were increased in both fasting ( P = 0.02 ) and postpr and ial ( P = 0.02 ) periods , and a greater amount of infused labeled fatty acid appeared in VLDL triacylglycerol after the HC diet than after the higher-fat diet ( P = 0.05 ) . Significantly less 13CO2 was exhaled after the HC diet ( P = 0.04 ) and significantly less production of 13CO2 was seen across forearm muscle ( P = 0.04 ) . Systemic 3-hydroxybutyrate was significantly lower , postpr and ially , after the HC diet ( P = 0.02 ) . CONCLUSION Metabolic alterations suggestive of repartitioning of fatty acids away from oxidation toward esterification in both liver and muscle occur in response to short-term adaptation to a HC diet Dietary guidelines for the general population and for the management of obesity , diabetes and heart disease suggest a reduction in dietary fat , and in particular dietary saturated fatty acids ( SFA ) . In order to achieve the recommended levels , changes in food choice patterns are required . Foods are consumed in combination with other foods , and these combinations are often recognizable as cuisine patterns . In this study we examined the food choice patterns of a group of 63 adults with existing type 2 diabetes mellitus who completed a 12 month dietary intervention trial aim ed at changing dietary fat under ' free living ' conditions . In both lower fat ( LF , 27 % ) and modified fat ( MF , 37%E ) groups , a reduction in dietary SFA and an increase in polyunsaturated fat were required , with an additional requirement to increase dietary monounsaturated fat in the MF group . The usual diets of the study sample were on average low in total fat ( 27%E ) , but high in saturated fat ( 12%E ) . Those already consuming total fat at the level concordant with their allocation ( LF or MF ) achieved targets faster than those with a discordant allocation , but there was no significant effect of usual diet on time of target achievement at 12 months . At 6 months , those achieving dietary fat targets had changed to low fat dairy products and leaner meats , were having more spreads , oils , and nuts and were consuming takeaway meals less than twice a week . Contributions to dietary fat shifted from takeaway foods , meat , dairy products and cakes to spreads , oils and nuts . The modified fat and low fat groups chose more Mediterranean and South East Asian cuisines respectively . In this study sample , usual dietary patterns had an initial impact on change in the diet , but identifiable changes in food choice patterns and the adoption of certain cuisines that combined foods indicative of the dietary guidelines result ed in successful achievement of dietary fat targets BACKGROUND The efficacy of ad libitum low-fat diets in reducing body weight and fat in overweight and obese adults remains controversial . METHODS We examined the effect of a 12-week low-fat , high-complex carbohydrate diet alone ( HI-CHO ) and in combination with aerobic exercise training ( HI-CHO + EX ) on body weight and composition in 34 individuals with impaired glucose tolerance ( 20 women and 14 men ; mean + /- SEM age , 66 + /- 1 years ) . Participants were r and omly assigned to a control diet ( 41 % fat , 14 % protein , 45 % carbohydrates , and 7 g of fiber per 1000 kcal ) , a HI-CHO diet ( 18 % fat , 19 % protein , 63 % carbohydrates , and 26 g of fiber per 1000 kcal ) , or a HI-CHO diet plus endurance exercise 4 d/wk , 45 min/d , at 80 % peak oxygen consumption ( HI-CHO + EX ) . Participants were provided 150 % of estimated energy needs and were instructed to consume food ad libitum . Total food intake , body composition , resting metabolic rate , and substrate oxidation were measured . RESULTS There was no significant difference in total food intake among the 3 groups and no change in energy intake over time . The HI-CHO + EX and HI-CHO groups lost more body weight ( -4.8 + /- 0.9 kg [ P=.003 ] and -3.2 + /- 1.2 kg [ P=.02 ] ) and a higher percentage of body fat ( -3.5 % + /- 0.7 % [ P=.01 ] and -2.2 % + /- 1.2 % [ P=.049 ] ) than controls ( -0.1 + /- 0.6 kg and 0.2 % + /- 0.6 % ) . In addition , thigh fat area decreased in the HI-CHO ( P=.003 ) and HI-CHO + EX ( P<.001 ) groups compared with controls . High carbohydrate intake and weight loss did not result in a decreased resting metabolic rate or reduced fat oxidation . CONCLUSION A high-carbohydrate diet consumed ad libitum , with no attempt at energy restriction or change in energy intake , results in losses of body weight and body fat in older men and women 
    Output:
    
Results : There was no evidence that variations of a typical , non-experimental diet influenced rate or ratio of substrate utilization , however there may be an upper and lower threshold for when macronutrient composition may directly alter preferences for fuel oxidation rates during a fasted state .
Conclusion : This review indicates that macronutrient composition of a wide range of typical , non-experimental dietary fat and carbohydrate intakes has no effect on fasting substrate oxidation .
This suggests that strict control of dietary intake prior to fasting indirect calorimetry measurements may be an unnecessary burden for study participants .