Can simply smelling chocolate before a workout help you train harder? A new study suggests that chocolate aromas may increase resistance exercise volume in a fasted state, offering a surprising glimpse into how our sense of smell influences appetite, motivation and physical performance.
Imagine walking into the gym after an overnight fast. You have not eaten breakfast, your stomach is rumbling, and your workout feels like it will be an uphill battle.
Now imagine that instead of reaching for a snack, you simply smell dark chocolate.
According to new research from the University of Malaya published in the Frontiers in Physiology, that seemingly odd strategy may actually help you complete more repetitions during resistance training (without eating a single bite).
While the findings are still preliminary, they reveal just how powerful our sense of smell can be in shaping not only our appetite, but potentially our exercise performance as well.
Can Smelling Chocolate Improve My Workout?
Researchers recruited 23 healthy men who had been resistance training for at least two years. Each participant completed three separate workout sessions after fasting overnight for at least 10 hours.
Before and during each workout, they were exposed to one of three scents:
- 90% dark chocolate
- 60% milk chocolate
- Water (control)
Participants repeatedly smelled the assigned scent for 30 seconds before exercise and between sets, before performing leg extensions at 80% of their 10-repetition maximum until they could no longer continue. Nobody actually ate any chocolate, unfortunately.
The researchers then compared how many repetitions and sets each participant completed under each condition.
A Surprising Boost From the Smell of Chocolate
The results were interesting. Compared with the water control, participants completed:
- 18 more total repetitions after smelling dark chocolate.
- 9 more repetitions after smelling milk chocolate.
- Those exposed to dark chocolate also completed approximately one additional set before reaching exhaustion.
Perhaps even more interesting was that participants did not report feeling that the workout was harder.
Of course, perceived exertion rose naturally as the workout progressed, but there were no meaningful differences between the chocolate groups and control group. In other words, they appeared to perform more work without feeling as though they were working significantly harder.
Why Would Smell Affect Exercise?
The answer may lie in the close connection between our nose and our brain.
The olfactory system communicates directly with brain regions involved in emotion, reward, memory and appetite. Certain food smells can trigger physiological responses before food even reaches the stomach — known as cephalic phase responses.
These anticipatory responses may include changes in salivation, digestive activity and hormones involved in hunger and satiety.
In this study, the two chocolate scents appeared to influence participants differently.
Dark Chocolate
Participants exposed to the dark chocolate aroma consistently reported:
- Less hunger
- Lower desire to eat
- Greater feelings of fullness
- Lower expectations of how much food they could consume
These effects were present before exercise even began.
Milk Chocolate
Milk chocolate produced a slightly different psychological response.
Participants rated it as significantly more pleasant to smell, but it did not suppress appetite to the same extent as dark chocolate. Despite this, exercise performance still improved compared with the control condition.
Does Appetite Really Influence Exercise Performance?
Interestingly, the researchers found that participants who felt less hungry before exercise generally performed better.
Across all sessions:
- Lower hunger was associated with more repetitions and more completed sets.
- Greater feelings of fullness were also linked to better performance.
- However, statistical analyses could not prove that these appetite changes directly caused the improved performance.
The study found an association, but it cannot yet conclude that reducing hunger is the mechanism responsible for the extra repetitions.
How Could It Work?
Exactly how this all improves exercise performance is still not fully understood. However, it is postulated that during a fasted workout, hunger itself can become another source of discomfort alongside physical fatigue. When hunger is high, it competes with the motivation to continue exercising. By temporarily suppressing hunger, participants may have been better able to focus on the exercise task rather than the desire to eat.
This mechanism has yet to be proven.
Should I Start Smelling Chocolate Before My Workouts?
Not quite – the authors describe the study as exploratory and emphasise that much more research is needed.
First of all, the study included only a very small group (23) young, resistance-trained men, meaning the findings may not apply to women, older adults or recreational exercisers.
Secondly, the study workout consisted only of a leg extension exercise rather than a full-body training session.
Thirdly, researchers also did not measure hormones such as ghrelin or GLP-1, brain activity or other physiological markers that could explain why the effect occurred.
Finally, as the control condition was simply odourless water, some participants may have guessed when they were receiving the placebo condition, potentially influencing expectations.
What Does This Mean for Me?
Although it is too early to recommend chocolate aromas as a performance aid, the findings raise an intriguing possibility.
Unlike caffeine, sports drinks or supplements, smelling food delivers no calories and avoids gastrointestinal discomfort.
If future studies confirm these findings across larger and more diverse populations, carefully selected food aromas could become another tool to help athletes train under fasted conditions or during periods of calorie restriction.
For now, however, the evidence should be viewed with intrigue rather than practical guidance. Smelling chocolate before leg day is unlikely to become the next gym trend overnight…just keep this away from FitTok.
