Background: Preexercise food intake enhances exercise performance due, in part, to the provision of exogenous carbohydrate. Food intake also suppresses hunger, but the specific influence of hunger on exercise performance has not been investigated. This study aimed to manipulate hunger by altering preexercise meal viscosity to examine whether hunger influences performance.
Methods: Sixteen resistance-trained males completed 2 experimental trials ingesting either high viscosity semisolid (SEM) and low viscosity liquid (LIQ) carbohydrate-containing meals 2 hours before performing 4 sets of back squat (85 [22] kg) and bench press (68 [13] kg) to failure at 90% 10-repetition maximum. Subjective hunger/fullness as well as plasma concentrations of glucose, insulin, ghrelin, and peptide tyrosine-tyrosine were measured before and periodically after the meal. Repetitions completed in sets were used to determine exercise performance.
Results: Hunger was lower, and fullness was greater during SEM compared with LIQ immediately before and during exercise (P < .05). Total repetitions completed for back squat were approximately 10% greater in SEM (SEM 57 [9]; LIQ 51 [7] repetitions; P = .001) with no difference in bench press repetitions (SEM 48 [11]; LIQ 48 [10] repetitions; P = .621). Postprandial glucose concentrations were greater during LIQ (12% increase in peak glucose) but were similar throughout exercise.
Conclusion: This study demonstrates that exercise performance in back squat was increased in the SEM trial concomitant to a reduction in hunger. Therefore, this study provides novel data that suggest that exercise performance might be influenced by hunger, at least for resistance exercise.
Keywords: appetite; liquid meal; satiety; solid meal; weight training.