A small new study found that men who smelled dark chocolate before and during a leg workout completed significantly more repetitions than those who smelled water. The research, published in Frontiers in Physiology, also found that participants who inhaled the chocolate scent reported feeling less hungry and fuller during the session.
According to Healthline, researchers recruited 23 healthy men who regularly participated in resistance training. Each participant completed three laboratory sessions, separated by at least four days, testing one odor per session. The three odors were 90% dark chocolate, 60% milk chocolate, and a water-based control. All sessions took place after an overnight fast of at least 10 hours.
Before exercising, participants smelled one of the prepared odor samples for 30 seconds at several time points while rating their hunger, fullness, desire to eat, and how pleasant they found the scent. They then performed repeated sets of leg extensions.
The dark chocolate scent produced the strongest results. The milk chocolate scent also improved performance compared to water, though to a lesser extent, and appeared to produce a different psychological response than the dark chocolate condition.
Researchers suspect that certain scents trigger physiological changes that may affect physical performance, though the exact mechanism remains unclear. The study adds to existing research showing that other odors, including peppermint, ammonia, lavender, and citrus, have also been shown to influence athletic performance.
Marie-Eve Mathieu, PhD, Canada Research Chair in physical activity and juvenile obesity at Université de Montréal, was not involved in the study but reviewed the findings. "Their findings, showing greater improvements in performance with dark chocolate, align well with other findings in the literature, where lower appetite and higher fullness are associated with better performance," she said.
Despite the results, experts caution against reading too much into a single exploratory study. The study was relatively small, involved only young resistance-trained men, and evaluated performance during a single type of exercise performed after an overnight fast.
Kristin Kirkpatrick, president of KAK Consulting and a dietitian at the Cleveland Clinic Department of Wellness and Preventive Medicine in Ohio, offered a direct caution. "We need to be cautious about drawing broad conclusions," she said.
Researchers and commentators alike described the findings as an intriguing first step rather than definitive proof. Future studies would need to involve larger and more diverse populations, multiple exercise types, and different testing conditions before stronger conclusions could be drawn.
