title: No effect of 1 or 7 d of green tea extract ingestion on fat oxidation during exercise.
abstract: OBJECTIVE
  The aim of this study was to investigate the effects of 1 and 7 d of green tea extract (GTE) ingestion on whole body fat oxidation during moderate-intensity exercise.
  
  
  METHODS
  Thirty-one men completed two exercise trials (60-min cycle, 50% Wmax). After the baseline trial (day 0), subjects were randomly assigned to one of three conditions involving a week supplementation of the following: 1) 7 d of placebo, 2) 6 d of placebo followed by 1 d of GTE (GTE1), and 3) 7 d of GTE ingestion (GTE7). The morning after the supplementation week, subjects consumed an additional supplement and completed a second exercise trial (day 8). V˙O2 and V˙CO2 measurements were taken during exercise to calculate whole body fat oxidation rates. Blood samples, for analysis of plasma fatty acids (FA), glycerol, and epigallocatechin gallate, were collected at rest and during exercise.
  
  
  RESULTS
  On day 8, the plasma kinetics and maximal plasma concentrations of epigallocatechin gallate were similar in the GTE1 and GTE7 group (206 ± 28 and 216 ± 25 ng·mL, respectively). One day of GTE ingestion did not affect markers of lipolysis during the exercise bout. Seven days of GTE ingestion significantly increased plasma glycerol during exercise (P = 0.045) and plasma FA during exercise (P = 0.020) as well as at rest (P = 0.046). However, fat oxidation did not change in any of the groups.
  
  
  CONCLUSIONS
  There was no effect of 1 d of GTE ingestion on markers of lipolysis or fat oxidation during exercise. Seven days of GTE ingestion increased lipolysis, indicated by increased plasma FA and glycerol concentrations, but did not result in significant changes in fat oxidation.
authors.affiliation: Human Performance Laboratory, School of Sport and Exercise Sciences, University of Birmingham, Birmingham, UK.
authors.forename: Rebecca K
authors.initials: RK
authors.lastname: Randell
authors.forename: Adrian B
authors.initials: AB
authors.lastname: Hodgson
authors.forename: Silvina B
authors.initials: SB
authors.lastname: Lotito
authors.forename: Doris M
authors.initials: DM
authors.lastname: Jacobs
authors.forename: Niels
authors.initials: N
authors.lastname: Boon
authors.forename: David J
authors.initials: DJ
authors.lastname: Mela
authors.forename: Asker E
authors.initials: AE
authors.lastname: Jeukendrup
mesh_terms: D000273:Adipose Tissue / Q000378:metabolism*; D000293:Adolescent; D000328:Adult; D002392:Catechin / Q000031:analogs & derivatives / Q000627:therapeutic use; D004311:Double-Blind Method; D015444:Exercise / Q000502:physiology*; D005227:Fatty Acids / Q000378:metabolism; D005260:Female; D005990:Glycerol / Q000378:metabolism; D006801:Humans; D008066:Lipolysis / Q000502:physiology*; D008297:Male; D010101:Oxygen Consumption / Q000502:physiology; D010936:Plant Extracts / Q000008:administration & dosage*; D011480:Protease Inhibitors / Q000008:administration & dosage*; D055815:Young Adult
chemical_list: D005227:Fatty Acids; D010936:Plant Extracts; D011480:Protease Inhibitors; D002392:Catechin; C045651:epigallocatechin gallate; D005990:Glycerol