title: Ghrelin and glucagon-like peptide 1 concentrations, 24-h satiety, and energy and substrate metabolism during a high-protein diet and measured in a respiration chamber.
abstract: BACKGROUND
  The mechanism of protein-induced satiety remains unclear.
  
  
  OBJECTIVE
  The objective was to investigate 24-h satiety and related hormones and energy and substrate metabolism during a high-protein (HP) diet in a respiration chamber.
  
  
  METHODS
  Twelve healthy women aged 18-40 y were fed in energy balance an adequate-protein (AP: 10%, 60%, and 30% of energy from protein, carbohydrate, and fat, respectively) or an HP (30%, 40%, and 30% of energy from protein, carbohydrate, and fat, respectively) diet in a randomized crossover design. Substrate oxidation, 24-h energy expenditure (EE), appetite profile, and ghrelin and glucagon-like peptide 1 (GLP-1) concentrations were measured.
  
  
  RESULTS
  Sleeping metabolic rate (6.40 +/- 0.47 compared with 6.12 +/- 0.40 MJ/d; P < 0.05), diet-induced thermogenesis (0.91 +/- 0.25 compared with 0.69 +/- 0.24 MJ/d; P < 0.05), and satiety were significantly higher, and activity-induced EE (1.68 +/- 0.32 compared with 1.86 +/- 0.41; P < 0.05), respiratory quotient (0.84 +/- 0.02 compared with 0.88 +/- 0.03; P < 0.0005), and hunger were significantly lower during the HP diet. There was a tendency for a greater 24-h EE during the HP diet (P = 0.05). Although energy intake was not significantly different between the diet groups, the subjects were in energy balance during the HP diet and in positive energy balance during the AP diet. Satiety was related to 24-h protein intake (r2 = 0.49, P < 0.05) only during the HP diet. Ghrelin concentrations were not significantly different between diets. GLP-1 concentrations after dinner were higher during the HP than during the AP diet (P < 0.05).
  
  
  CONCLUSIONS
  An HP diet, compared with an AP diet, fed at energy balance for 4 d increased 24-h satiety, thermogenesis, sleeping metabolic rate, protein balance, and fat oxidation. Satiety was related to protein intake, and incidentally to ghrelin and GLP-1 concentrations, only during the HP diet.
authors.affiliation: Department of Human Biology, Maastricht University, Maastricht, The Netherlands. m.lejeune@HB.unimaas.nl
authors.forename: Manuela P G M
authors.initials: MP
authors.lastname: Lejeune
authors.forename: Klaas R
authors.initials: KR
authors.lastname: Westerterp
authors.forename: Tanja C M
authors.initials: TC
authors.lastname: Adam
authors.forename: Natalie D
authors.initials: ND
authors.lastname: Luscombe-Marsh
authors.forename: Margriet S
authors.initials: MS
authors.lastname: Westerterp-Plantenga
mesh_terms: D000293:Adolescent; D000328:Adult; D000596:Amino Acids / Q000378:metabolism; D019540:Area Under Curve; D001481:Basal Metabolism / Q000187:drug effects / Q000502:physiology; D001823:Body Composition / Q000502:physiology; D002153:Calorimetry, Indirect / Q000379:methods; D018592:Cross-Over Studies; D004044:Dietary Proteins / Q000008:administration & dosage*; D004305:Dose-Response Relationship, Drug; D002149:Energy Intake; D004734:Energy Metabolism / Q000502:physiology*; D004780:Environment, Controlled; D005260:Female; D054439:Ghrelin; D052216:Glucagon-Like Peptide 1 / Q000097:blood*; D006801:Humans; D010084:Oxidation-Reduction; D010101:Oxygen Consumption; D036361:Peptide Hormones / Q000097:blood*; D012527:Satiation / Q000187:drug effects / Q000502:physiology*; D016037:Single-Blind Method; D022722:Thermogenesis / Q000187:drug effects / Q000502:physiology
chemical_list: D000596:Amino Acids; D004044:Dietary Proteins; D054439:Ghrelin; D036361:Peptide Hormones; D052216:Glucagon-Like Peptide 1