title: Increased 24-hour ad libitum food intake is associated with lower plasma irisin concentrations the following morning in adult humans.
abstract: BACKGROUND
  The relationship between food intake and irisin concentrations in humans is unclear.
  
  
  OBJECTIVE
  To determine whether the previous day's intake impacts fasting plasma irisin concentrations, or whether fasting irisin concentrations associate with subsequent ad libitum food intake.
  
  
  METHODS
  Sixty-six nondiabetic adults (42 men) were admitted for a study of the determinants of energy intake. After 6 days of a weight maintaining diet, ad libitum energy intake over 3 days was assessed using a vending machine paradigm. Fasting plasma irisin concentrations were measured on the morning of the second day of the vending period.
  
  
  RESULTS
  There were no correlations between irisin and demographic or anthropometric parameters. On day 1, subjects consumed 144 ± 52% of weight maintaining energy needs. Every additional 500 kcal consumed on day 1 associated with a 3.4% lower irisin concentration the following morning (95% CI -6.2, -0.4%, p = 0.01; adjusted for age, sex and race). If energy intake was expressed as a percentage of weight maintaining energy needs, every 10% increase associated with a 1.9% lower irisin concentration (95% CI -3.7, -0.1%; adjusted p = 0.02). A 100 kcal increase in carbohydrate or fat consumption associated with a 1.3% (95% CI -2.5, -0.1%, p = 0.01) and a 0.6% (95% CI -1.1, -0.0%, p = 0.02) lower irisin concentration, respectively. There was no association between fasting irisin concentrations and subsequent energy intake on day 2 (r = 0.19, p = 0.1).
  
  
  CONCLUSIONS
  Higher ad libitum 24 h energy intake was associated with lower fasting irisin concentrations the following morning, but fasting irisin concentrations did not predict subsequent energy intake. The decrease in irisin concentrations with increased energy intake is consistent with the detrimental metabolic effects of overeating.
authors.affiliation: Phoenix Epidemiology and Clinical Research Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Phoenix, AZ, USA. Electronic address: mathias.schlogl@nih.gov.
authors.forename: Mathias
authors.initials: M
authors.lastname: Schlögl
authors.affiliation: Phoenix Epidemiology and Clinical Research Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Phoenix, AZ, USA.
authors.forename: Paolo
authors.initials: P
authors.lastname: Piaggi
authors.affiliation: Phoenix Epidemiology and Clinical Research Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Phoenix, AZ, USA.
authors.forename: Susanne B
authors.initials: SB
authors.lastname: Votruba
authors.affiliation: Clinical Core Laboratory, National Institute of Diabetes and Digestive and Kidney Diseases, Bethesda, MD, USA.
authors.forename: Mary
authors.initials: M
authors.lastname: Walter
authors.affiliation: Phoenix Epidemiology and Clinical Research Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Phoenix, AZ, USA.
authors.forename: Jonathan
authors.initials: J
authors.lastname: Krakoff
authors.affiliation: Phoenix Epidemiology and Clinical Research Branch, National Institute of Diabetes and Digestive and Kidney Diseases, National Institutes of Health, Phoenix, AZ, USA.
authors.forename: Marie S
authors.initials: MS
authors.lastname: Thearle
mesh_terms: D000328:Adult; D004040:Dietary Carbohydrates / Q000378:metabolism*; D004041:Dietary Fats / Q000378:metabolism*; D004435:Eating / Q000523:psychology*; D002149:Energy Intake; D005215:Fasting / Q000097:blood / Q000378:metabolism; D005260:Female; D005353:Fibronectins / Q000097:blood*; D006801:Humans; D008297:Male; D013997:Time Factors; D055815:Young Adult
chemical_list: D004040:Dietary Carbohydrates; D004041:Dietary Fats; C577593:FNDC5 protein, human; D005353:Fibronectins
keywords: Ad libitum food intake; Irisin