title: Effect of time interval between food intake and exercise on substrate oxidation during exercise in obese and lean children.
abstract: OBJECTIVE
  Exercise induces adaptations in fat metabolism favourable to the treatment of obesity. However, time interval between meal and exercise alters substrate bioavailability and oxidation during exercise. The aim of this study was therefore to investigate the effect of time interval between food intake and exercise on substrate oxidation rates in obese and lean children.
  
  
  METHODS
  The metabolic responses to exercise of nine obese children (10.3 ± 1.8 years; %body fat: 36.1 ± 6.1) and seven lean children (9.2 ± 1.6 years; %body fat: 22.2 ± 4.1) were compared 1 h (time interval 1, TI1) and 3 h (TI3) after a standardized breakfast.
  
  
  RESULTS
  Despite significantly lower plasma glucose and insulin concentrations and large effect size suggesting a higher plasma FFA availability (lean, 1.43, obese 0.98), fat oxidation was not significantly increased in TI3 compared to TI1 in both lean and obese children. Fat oxidation contributed marginally to energy expenditure during exercise (<20%) in both conditions and groups but was moderately increased during TI3 compared to TI1 in lean children (effect size: 0.54).
  
  
  CONCLUSIONS
  The low contribution of fat oxidation to energy expenditure during exercise in obese and lean children fed 3 h before exercise questions the efficacy of moderate intensity exercise to favourably affect fat balance.
authors.affiliation: Laboratoire Universitaire de Biologie des Activités Physiques et Sportives, Université Blaise Pascal, Clermont-Ferrand, Batiment de Biologie B, Campus Universitaire des Cézeaux, 63177 Aubière Cedex, France. julien.aucouturier@univ-lille2.fr
authors.forename: Julien
authors.initials: J
authors.lastname: Aucouturier
authors.forename: Laurie
authors.initials: L
authors.lastname: Isacco
authors.forename: David
authors.initials: D
authors.lastname: Thivel
authors.forename: Nicole
authors.initials: N
authors.lastname: Fellmann
authors.forename: Jean-Michel
authors.initials: JM
authors.lastname: Chardigny
authors.forename: Martine
authors.initials: M
authors.lastname: Duclos
authors.forename: Pascale
authors.initials: P
authors.lastname: Duché
mesh_terms: D000273:Adipose Tissue / Q000502:physiology; D000886:Anthropometry; D001481:Basal Metabolism; D001786:Blood Glucose / Q000032:analysis; D001823:Body Composition / Q000502:physiology; D002153:Calorimetry, Indirect; D002648:Child; D004435:Eating / Q000502:physiology*; D004734:Energy Metabolism / Q000502:physiology; D015444:Exercise / Q000502:physiology*; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005260:Female; D006801:Humans; D007328:Insulin / Q000097:blood; D008297:Male; D009765:Obesity / Q000378:metabolism*; D010084:Oxidation-Reduction; D011897:Random Allocation
chemical_list: D001786:Blood Glucose; D005230:Fatty Acids, Nonesterified; D007328:Insulin