title: Impaired fat-induced thermogenesis in obese subjects: the NUGENOB study.
abstract: OBJECTIVE
  To study energy expenditure before and 3 hours after a high-fat load in a large cohort of obese subjects (n = 701) and a lean reference group (n = 113).
  
  
  METHODS
  Subjects from seven European countries underwent a 1-day clinical study with a liquid test meal challenge containing 95% fat (energy content was 50% of estimated resting energy expenditure). Fasting and 3-hour postprandial energy expenditures, as well as metabolites and hormones, were determined.
  
  
  RESULTS
  Obese subjects had a reduced postprandial energy expenditure after the high-fat load, independent of body composition, age, sex, research center, and resting energy expenditure, whereas within the obese group, thermogenesis increased again with increasing BMI category. Additionally, insulin resistance, habitual physical activity, postprandial plasma triacylglycerols, and insulin were all independently positively related to the postprandial energy expenditure. Resting energy expenditure, adjusted for fat-free mass, increased with degree of obesity, a difference that disappeared after adjustment for fat mass. Furthermore, insulin resistance, fasting plasma free fatty acids, and cortisol were positively associated, whereas fasting plasma leptin and insulin-like growth factor-1 were negatively associated, with resting energy expenditure.
  
  
  CONCLUSIONS
  The 3-hour fat-induced thermogenic response is reduced in obesity. It remains to be determined whether this blunted thermogenic response is a contributory factor or an adaptive response to the obese state.
authors: Department of Human Biology, Nutrition and Toxicology Research Institute Maastricht, Maastricht, The Netherlands. E.Blaak@HB.Unimaas.nl
authors: Ellen E
authors: EE
authors: Blaak
authors: Gabby
authors: G
authors: Hul
authors: Camilla
authors: C
authors: Verdich
authors: Vladimir
authors: V
authors: Stich
authors: J Alfredo
authors: JA
authors: Martinez
authors: Martin
authors: M
authors: Petersen
authors: Edith F M
authors: EF
authors: Feskens
authors: Kishor
authors: K
authors: Patel
authors: Jean Michel
authors: JM
authors: Oppert
authors: Pierre
authors: P
authors: Barbe
authors: Søren
authors: S
authors: Toubro
authors: Jan
authors: J
authors: Polak
authors: Ingalena
authors: I
authors: Anderson
authors: Arne
authors: A
authors: Astrup
authors: Ian
authors: I
authors: Macdonald
authors: Dominique
authors: D
authors: Langin
authors: Thorkild
authors: T
authors: Sørensen
authors: Wim H
authors: WH
authors: Saris
mesh_terms: D017667:Adipocytes / Q000502:physiology*; D000328:Adult; D001481:Basal Metabolism / Q000502:physiology; D015992:Body Mass Index; D004734:Energy Metabolism / Q000502:physiology; D005230:Fatty Acids, Nonesterified / Q000097:blood; D005260:Female; D006801:Humans; D006854:Hydrocortisone / Q000097:blood; D007328:Insulin / Q000097:blood; D008297:Male; D008875:Middle Aged; D009765:Obesity / Q000097:blood / Q000503:physiopathology*; D019518:Postprandial Period; D022722:Thermogenesis / Q000502:physiology*; D014280:Triglycerides / Q000097:blood
chemical_list: D005230:Fatty Acids, Nonesterified; D007328:Insulin; D014280:Triglycerides; D006854:Hydrocortisone