Chocolate odor enhances resistance exercise performance through appetite suppression in the fasted state: an exploratory study

Introduction Olfactory stimuli may alter appetite, affective responses, and exercise performance through psychobiological processes. However, whether odor-induced changes in appetite and pleasantness translate into measurable improvements in resistance exercise performance remains unclear. This exploratory study investigated whether exposure to chocolate-related odors alters appetite perception, odor pleasantness, and resistance exercise capacity in moderately trained men. Methods Twenty-three participants completed a randomized, double-blind, crossover trial with three odor conditions presented as freshly prepared liquid stimuli: 90% dark chocolate, 60% milk chocolate, and a water-based control. Appetite perception and odor pleasantness were assessed using 100-mm visual analog scales, and perceived exertion was assessed using the Borg CR10 scale. Ratings were obtained at baseline and after odor exposure. Participants then performed repeated 10-repetition leg-extension sets at 80% of 10RM to volitional exhaustion with 3.5-min rest intervals. Odors were presented before each set, followed by assessments of appetite, pleasantness, and ratings of perceived exertion. Results Condition significantly affected total repetitions (Wald χ ²(2) = 71.15, p < 0.01) and total sets (Wald χ ²(2) = 21.27, p < 0.01). Total repetitions were greater with 90% dark chocolate than with control (+18, 95% CI 13.8 to 22.1, p < 0.01) and greater with 60% milk chocolate than with control (+9, p < 0.01). Ratings of perceived exertion increased across sets ( p < 0.01) but did not differ between conditions. Before exercise, 90% dark chocolate reduced appetite-related ratings, whereas 60% milk chocolate increased odor pleasantness. Discussion These findings indicate that chocolate-related odors can modulate appetite and hedonic responses while increasing resistance-exercise volume, without clear increases in post-set perceived exertion. Chocolate-related odors may offer a non-nutritive approach to support fasted resistance exercise, although further work is needed to confirm the mechanisms and generalizability of these effects.