A small new study suggests that simply inhaling the scent of dark chocolate before and during a leg workout may help people complete more repetitions and feel less hungry afterward. The findings add to growing evidence that smells can influence physical performance, appetite, and perception — though the results are preliminary and limited in scope.
What the study did
Researchers enrolled 23 healthy, resistance-trained young men. Each participant attended three laboratory sessions separated by at least four days. At each visit they were exposed to one of three odors: 90% dark chocolate, 60% milk chocolate, or a water-based control. All testing occurred after an overnight fast of at least 10 hours.
Before exercise and between sets, participants inhaled the assigned scent for about 30 seconds and rated their hunger, fullness, desire to eat, and how pleasant the scent was. They then performed repeated sets of leg extensions to failure.
Key findings
– Smelling 90% dark chocolate was associated with the largest performance boost: participants completed an average of 18 more repetitions across the session than they did in the control (water) condition. They also completed about one additional set compared with milk chocolate or control.
– The 60% milk chocolate scent produced a smaller improvement — roughly nine more repetitions than control — and was consistently rated as more pleasant than dark chocolate or the control.
– Dark chocolate aroma reduced participants’ reported hunger, desire to eat, and expected prospective food intake, while increasing feelings of fullness. Milk chocolate did not produce the same appetite-suppressing effect.
Possible mechanisms
The exact reasons scents might influence performance aren’t established. The authors propose several possibilities, including a cephalic-phase or endocrine response: anticipating food via smell can trigger hormonal and physiological changes before any food is consumed. Scent cues might also alter perception of effort, motivation, or arousal, all of which can affect how many repetitions someone completes.
How this fits with other research
This study aligns with prior work showing modest effects of odors on exercise. For example:
– Peppermint has been linked in some studies to small improvements in sprinting, running, push-ups, and perceived exertion.
– Ammonia (smelling salts) can increase alertness and is sometimes used in weight rooms for short-term arousal.
– Lavender has been studied for calming and recovery effects.
– Citrus scents may improve mood and well-being during activity.
Why to be cautious
Experts emphasize important limitations of the current study:
– Small sample size (23 participants).
– Participants were all young, resistance-trained men, so results may not generalize to women, older adults, untrained people, or other populations.
– Only one exercise (leg extension) was tested, and sessions were performed in a fasted state; effects could differ with other exercises or feeding conditions.
– The study is exploratory and not definitive proof that sniffing chocolate will reliably boost performance across contexts.
Practical takeaway
Sniffing chocolate, mint, or citrus is low risk and may provide a small performance or perceptual benefit for some people. The improvements reported in this study were modest — enough to be noticeable for some trainees but not transformative — and likely vary between individuals and situations. If a particular scent makes you feel more focused, less hungry, or more capable, it may be worth trying as a simple, safe adjunct to your usual preworkout routine. However, it should not replace established training, nutrition, and recovery practices.
What’s next
Researchers recommend replicating the finding in larger, more diverse samples and testing different exercises, intensities, and nutritional states. Deeper investigation of physiological mechanisms — for example, hormonal responses triggered by smell — would help clarify why some scents affect performance and appetite.
Bottom line
This exploratory study offers an intriguing hint that the aroma of dark chocolate could help trained men eke out a few extra reps during a leg workout while reducing hunger sensations. The result is interesting but preliminary; more research is needed before scent-based strategies can be recommended as a reliable performance aid.