title: Effect of a 3-day high-fat feeding period on carbohydrate balance and ad libitum energy intake in humans.
abstract: OBJECTIVE
  A reduction in glycogen after the switch to an isoenergetic high-fat diet (HFD) might promote a compensatory increase in food intake to reestablish carbohydrate balance. We assessed the effect of an isoenergetic switch from a 49%-carbohydrate to 50%-fat diet on nutrient balance and ad libitum food intake. We hypothesized that carbohydrate balance would be inversely related to ad libitum energy intake.
  
  
  METHODS
  In 47 men and 11 women (22.6+/-0.4 years; 26.1+/-0.5 kg m(-2)), fuel balance was measured in a respiration chamber over 4 days. During the first day, an isoenergetic, high-carbohydrate diet was provided followed by a 3-day isoenergetic, HFD. At the end of this period and after 16 h of fasting, three options of foods (cookies, fruit salad and turkey sandwich) were offered ad libitum for 4 h. The relationships between post-chamber ad libitum intake and macronutrient oxidation and balance measured day-to-day and over the 4-day respiration chamber stay were studied.
  
  
  RESULTS
  After switching to a HFD, 24-h respiratory quotient decreased from 0.87+/-0.02 to 0.83+/-0.02 (P<0.0001) resulting in a 4-day cumulative carbohydrate, fat and protein balances of -183+/-368, 342+/-480 and 65+/-267 kcal, respectively. Cumulative energy balance (224+/-362 kcal per 4 days) did not influence ad libitum energy intake. However, we detected that 4-day carbohydrate balance was a positive and independent predictor of post-chamber ad libitum energy intake (R (2)=0.10; P=0.01), whereas no significant influence of fat and protein balances was found.
  
  
  CONCLUSIONS
  In response to an isoenergetic change from a high-carbohydrate to HFD, higher carbohydrate balance related to increased energy intake.
authors.affiliation: Pennington Biomedical Research Center, Baton Rouge, LA 70808, USA.
authors.forename: J E
authors.initials: JE
authors.lastname: Galgani
authors.forename: L
authors.initials: L
authors.lastname: de Jonge
authors.forename: M M
authors.initials: MM
authors.lastname: Most
authors.forename: G A
authors.initials: GA
authors.lastname: Bray
authors.forename: S R
authors.initials: SR
authors.lastname: Smith
mesh_terms: D000293:Adolescent; D000328:Adult; D004040:Dietary Carbohydrates / Q000008:administration & dosage / Q000378:metabolism*; D004041:Dietary Fats / Q000008:administration & dosage / Q000378:metabolism*; D002149:Energy Intake; D004734:Energy Metabolism; D005247:Feeding Behavior; D005260:Female; D005518:Food Preferences; D006003:Glycogen / Q000378:metabolism; D006801:Humans; D008297:Male; D009765:Obesity / Q000378:metabolism*; D010084:Oxidation-Reduction; D010101:Oxygen Consumption; D013997:Time Factors; D055815:Young Adult
chemical_list: D004040:Dietary Carbohydrates; D004041:Dietary Fats; D006003:Glycogen