title: Food reinforcement, energy intake, and macronutrient choice.
abstract: BACKGROUND
  Food is a powerful reinforcer that motivates people to eat. The relative reinforcing value of food (RRV(food)) is associated with obesity and energy intake and interacts with impulsivity to predict energy intake.
  
  
  OBJECTIVE
  How RRV(food) is related to macronutrient choice in ad libitum eating tasks in humans has not been studied; however, animal research suggests that sugar or simple carbohydrates may be a determinant of reward value in food. This study assessed which macronutrients are associated with food reinforcement.
  
  
  METHODS
  Two hundred seventy-three adults with various body mass indexes were assessed for RRV(food), the relative reinforcing value of reading, food hedonics, energy intake in an ad libitum taste test, and usual energy intake derived from repeated 24-h dietary recalls. Multiple regression was used to assess the relation between predictors of total energy and energy associated with macronutrient intake after control for age, sex, income, education, minority status, and other macronutrient intakes.
  
  
  RESULTS
  The results showed that the relative proportion of responding for food compared with reading (RRV(prop)) was positively related to body mass index, laboratory-measured energy intake, and usual energy intake. In addition, RRV(prop) was a predictor of sugar intake but not of total carbohydrate, fat, or protein intake.
  
  
  CONCLUSIONS
  These results are consistent with basic animal research showing that sugar is related to food reward and with the hypothesis that food reward processes are more strongly related to eating than are food hedonics. This trial was registered at clinicaltrials.gov as NCT00962117.
authors.affiliation: Department of Pediatrics, University at Buffalo School of Medicine and Biomedical Sciences, Buffalo, NY 14214-3000, USA. lhenet@buffalo.edu
authors.forename: Leonard H
authors.initials: LH
authors.lastname: Epstein
authors.forename: Katelyn A
authors.initials: KA
authors.lastname: Carr
authors.forename: Henry
authors.initials: H
authors.lastname: Lin
authors.forename: Kelly D
authors.initials: KD
authors.lastname: Fletcher
mesh_terms: D000328:Adult; D015992:Body Mass Index; D002149:Energy Intake; D005260:Female; D005502:Food; D005518:Food Preferences; D006801:Humans; D008297:Male; D012044:Regression Analysis; D012054:Reinforcement, Psychology