title: Food reward in active compared to inactive men: Roles for gastric emptying and body fat.
abstract: Habitual exercise could contribute to weight management by altering processes of food reward via the gut-brain axis. We investigated hedonic processes of food reward in active and inactive men and characterised relationships with gastric emptying and body fat. Forty-four men (active: n=22; inactive: n=22, BMI range 21-36kg/m(2); percent fat mass range 9-42%) were studied. Participants were provided with a standardised fixed breakfast and an ad libitum lunch meal 5h later. Explicit liking, implicit wanting and preference among high-fat, low-fat, sweet and savoury food items were assessed immediately post-breakfast (fed state) and again pre-lunch (hungry state) using the Leeds Food Preference Questionnaire. Gastric emptying was assessed by (13)C-octanoic acid breath test. Active individuals exhibited a lower liking for foods overall and a greater implicit wanting for low-fat savoury foods in the fed state, compared to inactive men. Differences in the fed state remained significant after adjusting for percent fat mass. Active men also had a greater increase in liking for savoury foods in the interval between breakfast and lunch. Faster gastric emptying was associated with liking for savoury foods and with an increase in liking for savoury foods in the postprandial interval. In contrast, greater implicit wanting for high-fat foods was associated with slower gastric emptying. These associations were independent of each other, activity status and body fat. In conclusion, active and inactive men differ in processes of food reward. The rate of gastric emptying may play a role in the association between physical activity status and food reward, via the gut-brain axis.
authors.affiliation: School of Exercise and Nutrition Sciences, Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Australia; Institute of Food and Health, University College Dublin, Dublin 4, Ireland. Electronic address: katyhorner@gmail.com.
authors.forename: Katy M
authors.initials: KM
authors.lastname: Horner
authors.affiliation: School of Psychology, Faculty of Medicine and Health, University of Leeds, UK.
authors.forename: Graham
authors.initials: G
authors.lastname: Finlayson
authors.affiliation: School of Exercise and Nutrition Sciences, Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Australia; Bond Institute of Health and Sport, Faculty of Health Sciences and Medicine, Bond University, Gold Coast, Australia.
authors.forename: Nuala M
authors.initials: NM
authors.lastname: Byrne
authors.affiliation: School of Exercise and Nutrition Sciences, Institute of Health and Biomedical Innovation, Queensland University of Technology, Brisbane, Australia.
authors.forename: Neil A
authors.initials: NA
authors.lastname: King
mesh_terms: D000273:Adipose Tissue / Q000502:physiology*; D000293:Adolescent; D000328:Adult; D000704:Analysis of Variance; D001066:Appetite / Q000502:physiology*; D005247:Feeding Behavior; D005518:Food Preferences / Q000502:physiology; D005746:Gastric Emptying / Q000502:physiology*; D006801:Humans; D008297:Male; D008875:Middle Aged; D010775:Photic Stimulation; D012201:Reward; D055815:Young Adult
keywords: Gastric emptying; Liking; Physical activity; Wanting