Chocolate Aroma Boosts Workout Volume Without Increasing Perceived Effort

Exposure to chocolate scents prior to and during strength training can help individuals complete additional repetitions without a corresponding increase in perceived exertion, according to research published in Frontiers in Physiology.

The study, led by Dr. Mohamed Nashrudin bin Naharudin, an assistant professor at the University of Malaya’s Faculty of Sports and Exercise Science, examined how olfactory cues interact with appetite and physical performance. “Seeing a substantial increase in repetitions without the athletes feeling like they were exerting themselves any harder is a fascinating psychobiological outcome,” Naharudin said.

Researchers tested 23 moderately trained men in their early to mid-20s. After fasting for at least 10 hours, participants were divided into three groups and exposed to either liquified dark chocolate (90% cocoa), liquified milk chocolate (60% cocoa), or odorless water as a control. The subjects then performed leg extensions while researchers tracked their performance and appetite levels during 30-second scent exposures between sets.

The two chocolate varieties produced distinct physiological and psychological effects. Dark chocolate aroma significantly reduced hunger and the desire to eat while increasing feelings of fullness compared to both the milk chocolate and control groups. In contrast, while participants found the milk chocolate scent more pleasant, it did not significantly alter hunger or appetite metrics.

In terms of physical performance, the aromas yielded measurable gains. Sniffing dark chocolate odor added approximately 18 extra repetitions to the participants’ leg extensions, while milk chocolate scent resulted in about nine additional repetitions compared to the water control.

Naharudin suggests these results may stem from learned associations between specific smells and food consumption. He explained that dark chocolate serves as a cue for a satiating food, potentially tricking the body into an anticipatory state of fullness. Conversely, the sweeter milk chocolate aroma may act as a hedonic reward, improving training volume by creating a pleasant sensory environment rather than altering metabolic hunger signals.

The authors acknowledged several limitations, noting that the study was small and limited to young, healthy men. Because the researchers did not measure blood hormones or neural activity, the exact biological pathways remain speculative. Additionally, the intensity of the chocolate scents may not have been perfectly matched, and the use of odorless water as a control may have allowed participants to discern their group assignment.

While chocolate has strong reward associations, the study authors believe other familiar and appealing food odors could produce similar effects, though this has yet to be tested. “A person likely needs to find the odor familiar and appealing – or at least not repulsive – to trigger the psychological shift in appetite that’s needed to see a performance boost,” Naharudin concluded.