title: Caffeine consumption around an exercise bout: effects on energy expenditure, energy intake, and exercise enjoyment.
abstract: Combining an exercise and nutritional intervention is arguably the optimal method of creating energy imbalance for weight loss. This study sought to determine whether combining exercise and caffeine supplementation was more effective for promoting acute energy deficits and manipulations to substrate metabolism than exercise alone. Fourteen recreationally active participants (mean ± SD body mass index: 22.7 ± 2.6 kg/m2) completed a resting control trial (CON), a placebo exercise trial (EX), and a caffeine exercise trial (EX+CAF, 2 × 3 mg/kg of caffeine 90 min before and 30 min after exercise) in a randomized, double-blinded design. Trials were 4 h in duration with 1 h of rest, 1 h of cycling at ∼65% power at maximum O2 consumption or rest, and a 2-h recovery. Gas exchange, appetite perceptions, and blood samples were obtained periodically. Two hours after exercise, participants were offered an ad libitum test meal where energy and macronutrient intake were recorded. EX+CAF resulted in significantly greater energy expenditure and fat oxidation compared with EX (+250 kJ; +10.4 g) and CON (+3,126 kJ; +29.7 g) (P < 0.05). A trend for reduced energy and fat intake compared with CON (-718 kJ; -8 g) (P = 0.055) was observed. Consequently, EX+CAF created a greater energy deficit (P < 0.05). Caffeine also led to exercise being perceived as less difficult and more enjoyable (P < 0.05). Combining caffeine with exercise creates a greater acute energy deficit, and the implications of this protocol for weight loss or maintenance over longer periods of time in overweight/obese populations should be further investigated.
authors.affiliation: School of Allied Health Sciences, Griffith University, Gold Coast, Queensland, Australia; Griffith Health Institute, Griffith University, Gold Coast, Queensland, Australia; and m.schubert@griffith.edu.au.
authors.forename: Matthew M
authors.initials: MM
authors.lastname: Schubert
authors.affiliation: School of Pharmacy, Griffith University, Gold Coast, Queensland, Australia; Griffith Health Institute, Griffith University, Gold Coast, Queensland, Australia; and.
authors.forename: Susan
authors.initials: S
authors.lastname: Hall
authors.affiliation: School of Human Movement Studies, University of Queensland, St. Lucia, Queensland, Australia.
authors.forename: Michael
authors.initials: M
authors.lastname: Leveritt
authors.affiliation: School of Pharmacy, Griffith University, Gold Coast, Queensland, Australia; Griffith Health Institute, Griffith University, Gold Coast, Queensland, Australia; and.
authors.forename: Gary
authors.initials: G
authors.lastname: Grant
authors.affiliation: School of Allied Health Sciences, Griffith University, Gold Coast, Queensland, Australia; Griffith Health Institute, Griffith University, Gold Coast, Queensland, Australia; and.
authors.forename: Surendran
authors.initials: S
authors.lastname: Sabapathy
authors.affiliation: School of Allied Health Sciences, Griffith University, Gold Coast, Queensland, Australia; Griffith Health Institute, Griffith University, Gold Coast, Queensland, Australia; and.
authors.forename: Ben
authors.initials: B
authors.lastname: Desbrow
mesh_terms: D000328:Adult; D002110:Caffeine / Q000008:administration & dosage*; D018592:Cross-Over Studies; D004311:Double-Blind Method; D002149:Energy Intake / Q000187:drug effects*; D004734:Energy Metabolism / Q000187:drug effects*; D015444:Exercise / Q000502:physiology / Q000523:psychology*; D005260:Female; D006801:Humans; D008297:Male; D010549:Personal Satisfaction; D055815:Young Adult
chemical_list: D002110:Caffeine
keywords: appetite; caffeine; exercise; exercise enjoyment; fat oxidation