***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: Objectives : Drinking green tea is associated with many health benefits , including increased fat oxidation . We tested the hypothesis that epigallocatechin-3-gallate ( EGCG ) , the main green tea catechin , increases  fat oxidation in obese men . Methods : Ten healthy overweight/obese males ( body mass index 31.3±0.8 kg/m2 ) were studied in a r and omized , placebo-controlled , double-blind crossover trial . Study supplements were low EGCG ( 300 mg ) , high EGCG ( 600 mg ) , caffeine ( 200 mg ) , EGCG/caffeine ( 300 mg/200 mg ) or placebo and were taken orally for 3 days . At the third day of supplementation , O2 consumption and CO2 production was measured by indirect calorimetry to assess energy expenditure and fat oxidation over 4 h each after overnight fasting and after a st and ardized test meal . Results : Energy expenditure was not affected by any supplementation , neither after overnight fasting nor after the test meal . During the first 2 h after overnight fasting , fat oxidation increased by 7.7 ( not significant , NS ) , 15.2 ( NS ) , 26.3 ( P<0.05 vs placebo ) and 35.4 % ( P<0.01 vs placebo and low EGCG ) , for low EGCG , high EGCG , caffeine and EGCG/caffeine , respectively . During the first 2 h after the meal , the mean increase in fat oxidation was 33.3 ( P<0.05 vs placebo ) , 20.2 ( NS ) , 34.5 ( P<0.05 vs placebo ) and 49.4 % ( P<0.05 vs placebo ) for low EGCG , high EGCG , caffeine and EGCG/caffeine , respectively . Conclusions : Low EGCG increases postpr and ial fat oxidation  in obese men and this to the same extent as 200 mg caffeine , whereas high EGCG does not exert this effect . Fasting fat oxidation is increased only by caffeine ( with or without EGCG ) . There is no synergism of low EGCG and 200 mg caffeine . Energy expenditure is not affected by EGCG It has been reported that green tea has a thermogenic effect , due to its caffeine content and probably also to the catechin , epigallocatechin-3-gallate ( EGCG ) . The main aim of the present study was to compare the effect of a mixture of green tea and Guarana extracts containing a fixed dose of caffeine and variable doses of EGCG on 24 h energy expenditure and fat oxidation .  Fourteen subjects took part to this r and omized , placebo-controlled , double-blind , cross-over study . Each subject was tested five times in a metabolic chamber to measure 24 h energy expenditure , substrate oxidation and blood pressure . During each stay , the subjects ingested a capsule of placebo or capsules containing 200 mg caffeine and a variable dose of EGCG ( 90 , 200 , 300 or 400 mg ) three times daily , 30 min before st and ardized meals . Twenty-four hour energy expenditure increased significantly by about 750 kJ with all EGCG-caffeine mixtures compared with placebo . No effect of the EGCG-caffeine mixture was observed for lipid oxidation . Systolic and diastolic blood pressure increased by about 7 and 5 mmHg , respectively , with the EGCG-caffeine mixtures compared with placebo . This increase was significant only for 24 h diastolic blood pressure . The main finding of the study was the increase in 24 h energy expenditure with the EGCG-caffeine mixtures . However , this increase was similar with all doses of EGCG in the mixtures Objectives : The development of obesity is characterized by an increase in adipose tissue mass and by concomitant and profound changes in almost all organ functions leading to diseases such as hypertension , diabetes mellitus and coronary heart disease . Recent data from human studies indicate that the consumption of green tea and green tea extracts may help reduce body weight , mainly body fat , by increasing postpr and ial thermogenesis and fat oxidation . However , human studies investigating the metabolic effects of the most predominant tea catechin , EGCG , alone are absent . Methods : In a r and omized double blind , placebo-controlled , cross-over pilot study , six overweight men were given 300 mg EGCG/d for 2d . Fasting and postpr and ial changes in energy expenditure ( EE ) and substrate oxidation were assessed . Results : Resting EE did not differ significantly between EGCG and placebo treatments , although during the first postpr and ial monitoring phase , respiratory quotient ( RQ ) values were significantly lower with EGCG compared to the placebo . Conclusions : These findings suggest that EGCG alone has the potential to increase fat oxidation in men and may thereby contribute to the anti-obesity effects of green tea . However , more studies with a greater sample size and a broader range of age and BMI are needed to define the optimum dose Background The efficacy of natural products ( NPs ) is being evaluated using r and omized controlled trials ( RCTs ) with increasing frequency , yet a search of the literature did not identify a widely accepted critical appraisal instrument developed specifically for use with NPs . The purpose of this project was to develop and evaluate a critical appraisal instrument that is sufficiently rigorous to be used in evaluating RCTs of conventional medicines , and also has a section specific for use with single entity NPs , including herbs and natural source d chemicals . Methods Three phases of the project included : 1 ) using experts and a Delphi process to reach consensus on a list of items essential in describing the identity of an NP ; 2 ) compiling a list of non-NP items important for evaluating the quality of an RCT using systematic review methodology to identify published instruments and then compiling item categories that were part of a vali date d instrument and /or had empirical evidence to support their inclusion and 3 ) conducting a field test to compare the new instrument to a published instrument for usefulness in evaluating the quality of 3 RCTs of a NP and in applying results to practice . Results Two Delphi rounds result ed in a list of 15 items essential in describing NPs . Seventeen item categories fitting inclusion criteria were identified from published instruments for conventional medicines . The new assessment instrument was assembled based on content of the two lists and the addition of a Review er 's Conclusion section . The field test of the new instrument showed good criterion validity . Participants found it useful in translating evidence from RCTs to practice . Conclusion A new instrument for the critical appraisal of RCTs of NPs was developed and tested . The instrument is distinct from other available assessment instruments for RCTs of NPs in its systematic development and validation . The instrument is ready to be used by pharmacy students , health care practitioners and academics and will continue to be refined as required OBJECTIVE Investigation of the effect of a green tea-caffeine mixture on weight maintenance after body weight loss in moderately obese subjects in relation to habitual caffeine intake . RESEARCH METHODS AND PROCEDURES A r and omized placebo-controlled double blind parallel trial in 76 overweight and moderately obese subjects , ( BMI , 27.5 + /- 2.7 kg/m2 ) matched for sex , age , BMI , height , body mass , and habitual caffeine intake was conducted . A very low energy diet intervention during 4 weeks was followed by 3 months of weight maintenance ( WM ) ; during the WM period , the subjects received a green tea-caffeine mixture ( 270 mg epigallocatechin gallate + 150 mg caffeine per day ) or placebo . RESULTS Subjects lost 5.9 + /-1.8 ( SD ) kg ( 7.0 + /- 2.1 % ) of body weight ( p < 0.001 ) . At baseline , satiety was positively , and in women , leptin was inversely , related to subjects ' habitual caffeine consumption ( p < 0.01 ) . High caffeine consumers reduced weight , fat mass , and waist circumference more than low caffeine consumers ; resting energy expenditure was reduced less and respiratory quotient was reduced more during weight loss ( p < 0.01 ) . In the low caffeine consumers , during WM , green tea still reduced body weight , waist , respiratory quotient and body fat , whereas resting energy expenditure was increased compared with a restoration of these variables with placebo ( p < 0.01 ) . In the high caffeine consumers , no effects of the green tea-caffeine mixture were observed during WM . DISCUSSION High caffeine intake was associated with weight loss through thermogenesis and fat oxidation and with suppressed leptin in women . In habitual low caffeine consumers , the green tea-caffeine mixture improved WM , partly through thermogenesis and fat oxidation BACKGROUND Current interest in the role of functional foods in weight control has focused on plant ingredients capable of interfering with the sympathoadrenal system . OBJECTIVE We investigated whether a green tea extract , by virtue of its high content of caffeine and catechin polyphenols , could increase 24-h energy expenditure ( EE ) and fat oxidation in humans . DESIGN Twenty-four-hour EE , the respiratory quotient ( RQ ) , and the urinary excretion of nitrogen and catecholamines were measured in a respiratory chamber in 10 healthy men . On 3 separate occasions , subjects were r and omly assigned among 3 treatments : green tea extract ( 50 mg caffeine and 90 mg epigallocatechin gallate ) , caffeine ( 50 mg ) , and placebo , which they ingested at breakfast , lunch , and dinner . RESULTS Relative to placebo , treatment with the green tea extract result ed in a significant increase in 24-h EE ( 4 % ; P < 0.01 ) and a significant decrease in 24-h RQ ( from 0.88 to 0.85 ; P < 0.001 ) without any change in urinary nitrogen . Twenty-four-hour urinary norepinephrine excretion was higher during treatment with the green tea extract than with the placebo ( 40 % , P < 0.05 ) . Treatment with caffeine in amounts equivalent to those found in the green tea extract had no effect on EE and RQ nor on urinary nitrogen or catecholamines . CONCLUSIONS Green tea has thermogenic properties and promotes fat oxidation beyond that explained by its caffeine content per se . The green tea extract may play a role in the control of body composition via sympathetic activation of thermogenesis , fat oxidation , or both BACKGROUND Green tea ( epigallocatechin gallate + caffeine ) and protein each were shown to improve body weight maintenance after weight loss . OBJECTIVE We investigated the effect of a green tea-caffeine mixture added to a high-protein ( HP ) diet on weight maintenance ( WM ) after body weight loss in moderately obese subjects . DESIGN A r and omized , placebo-controlled , double-blind parallel trial was conducted in 80 overweight and moderately obese subjects [ age ( mean + /- SD ) : 44 + /- 2 y ; body mass index ( BMI ; in kg/m(2 ) ) : 29.6 + /- 2.0 ] matched for sex , age , BMI , height , body mass , and with a habitually low caffeine intake . A very-low-energy diet intervention during 4 wk was followed by 3 mo of WM ; during the WM period , the subjects received a green tea-caffeine mixture ( 270 mg epigallocatechin gallate + 150 mg caffeine/d ) or placebo , both in addition to an adequate protein ( AP ) diet ( 50 - 60 g protein/d ) or an HP diet ( 100 - 120 g protein/d ) . RESULTS Subjects lost 7.0 + /- 1.6 kg , or 8.2 + /- 2.0 % , body weight ( P < 0.001 ) . During the WM phase , WM , resting energy expenditure , and fat-free mass ( FFM ) increased relatively in both the HP groups and in the AP + green tea-caffeine mixture group ( P < 0.05 ) , whereas respiratory quotient and body fat mass decreased , all compared with the AP + placebo group . Satiety increased only in both HP groups ( P < 0.05 ) . The green tea-caffeine mixture was only effective with the AP diet . CONCLUSION The green tea-caffeine mixture , as well as the HP diet , improved WM independently through thermogenesis , fat oxidation , sparing FFM , and , for the HP diet , satiety ; a possible synergistic effect failed to appear We assessed the effect of ingestion of green tea ( GT ) extract along with a low-energy diet ( LED ) on resting energy expenditure ( REE ) , substrate oxidation and body weight as GT has been shown to increase energy expenditure and fat oxidation in the short term in both animals and people . Forty-six overweight women ( BMI 27.6 ( sd 1.8 ) kg/m2 ) were fed in energy balance from day 1 to day 3 , followed by a LED with GT ( 1125 mg tea catechins + 225 mg caffeine/d ) or placebo ( PLAC ) from day 4 to day 87 . Caffeine intake was st and ardised to 300 mg/d . Energy expenditure was measured on days 4 and 32 . Reductions in weight ( 4.19 ( sd 2 
    Output:
    
AUTHORS ' CONCLUSIONS Green tea preparations appear to induce a small , statistically non-significant weight loss in overweight or obese adults .
Because the amount of weight loss is small , it is not likely to be clinical ly important .
Green tea had no significant effect on the maintenance of weight loss .
The remaining adverse events were judged to be mild to moderate