Sniffing chocolate before a workout may sound like a way to tempt yourself out of the gym and toward dessert. But a small new study suggests a quick whiff might help some people do more reps when they’re exercising on an empty stomach.
Trial participants who smelled chocolate before and between sets of leg extensions were able to do more total repetitions than they could after smelling a water-based placebo.
“The core takeaway is that briefly smelling chocolate can significantly increase the amount of weight lifting a person can do while fasting, without making the workout feel any harder,” says a coauthor of the study, Mohamed Nashrudin bin Naharudin, PhD, an assistant professor of sports and exercise science at the University of Malaya in Kuala Lumpur, Malaysia.
The findings suggest that you don’t always have to eat something to change how your body performs. “Sometimes, just giving your brain a quick sensory cue is enough to unlock extra energy,” he says.
The Scent of Chocolate Helped Men Push Harder
The study included 23 healthy men in their early to mid-twenties who were already doing resistance training at least twice a week. Each participant came to the lab after fasting overnight for at least 10 hours and completed three workout trials on different days.
In each trial, the men smelled one of three liquid samples in identical jars:
- 90 percent dark chocolate
- 60 percent milk chocolate
- A water-based control
They smelled the assigned sample for 30 seconds before exercise and again during rest periods in between sets.
Researchers had participants perform leg extensions, a seated exercise that works the muscles in the front of the thighs. The weight was set at 80 percent of each person’s 10-rep maximum, and participants kept going until they could no longer continue.
When they smelled dark chocolate, the men completed about 18 more reps on average than when they smelled water. Smelling milk chocolate led to a total of about 9 more reps than smelling water. Dark chocolate also helped participants complete about one more set than they could when they smelled water or milk chocolate.
The most interesting finding is the observed exercise performance bump from simply smelling dark chocolate after an overnight fast, says Sabrena Jo, PhD, the senior director of science and research at the American Council on Exercise, who wasn’t involved in the study.
“Just as important, the researchers found that the dark chocolate odor reduced feelings of hunger before exercise,” she says. That suggests the smell may have helped people feel less distracted by hunger and stay focused during the workout, says Dr. Jo.
Why the Aroma of Chocolate Might Help You Push Harder
The chocolate didn’t make anyone’s muscles stronger. The more likely explanation is that the smell changed the mental backdrop of the workout.
“Our sense of smell is closely connected to brain regions involved in emotion, memory, reward, and appetite. For many people, the smell of chocolate is associated with satisfaction and eating, even before a bite is taken,” says Jo.
Dr. Nashrudin bin Naharudin (who goes by Dr. Nash for short) says the two chocolate scents may have helped in different ways:
- Dark chocolate appeared to act more like an appetite cue, shifting people away from hunger and toward fullness.
- Milk chocolate, which was rated as more pleasant, may have worked more as a small reward during a tough workout.
Jo compares it to hearing a favorite song before exercise. “It doesn’t physically make your muscles stronger, but it can change how you feel,” she says.
These findings add to the idea that performance is shaped by more than fuel and muscle, says Jo. “Psychological factors — including attention, expectations, motivation, and even sensory experiences — can meaningfully influence how we perform,” she says.
Strengths and Limitations of the Study
The design of the study was a strength: Each participant tried all three conditions, so researchers could compare the same person after they smelled dark chocolate, milk chocolate, and the control. The exercise test and scent exposure were also standardized.
The study doesn’t prove why the chocolate smell seemed to help. For instance, the researchers didn’t measure appetite hormones, brain activity, or other body signals that could explain the mechanisms in play.
Additionally, there may have been slight variations in smell intensity between the chocolate samples, and since the water sample was odorless, that could have given participants a clue that they were smelling the control sample.
Because only young men who worked out regularly were included in the study, it’s unclear whether chocolate would have the same effect in other groups or scenarios; for instance women, older adults, recreational exercisers, endurance workouts, full-body strength sessions, or people who eat before exercise.
Could You Try This Yourself?
“This strategy is highly practical for anyone who practices intermittent fasting, time-restricted eating, or simply prefers early-morning workouts on an empty stomach,” says Nash.
“Eating a pre-workout snack right before heavy lifting can sometimes cause stomach cramps or sluggishness. Instead, people can use a ‘non-ingestive’ strategy: keeping a jar of high-quality cocoa powder or a pure chocolate extract in their gym bag,” he says.
A paced, 30-second sniff right before a workout and during rest periods between heavy sets could help maximize training volume and keep hunger pangs at bay without breaking a fast, says Nash.
He also cautions against smelling it continuously, because the nose can quickly become desensitized to a scent, which could make it less effective.
Factors to Consider First
Jo is more cautious about turning the finding into gym advice. “I wouldn’t recommend that people start carrying chocolate to the gym expecting a performance boost,” she says. Instead, she sees the study as an interesting reminder that surroundings and psychological state can influence how a workout feels.
Still, she says there’s relatively little downside or risk. For most healthy adults, exercising after an overnight fast is safe if the workout is moderate and they’re accustomed to it, says Jo.
“However, some people may experience dizziness, lightheadedness, fatigue, difficulty concentrating, or lower exercise performance when exercising without eating,” she says.
Those risks may be greater during longer or more intense workouts, in hot environments, or for people with diabetes or other medical conditions affecting blood sugar regulation, says Jo.
“The most important message is to pay attention to how your body responds. If fasting consistently leaves you feeling weak or unable to perform well, eating something before exercise is likely the better strategy,” she says.
For people who still want to experiment, the safest interpretation is low stakes: Smelling chocolate may be worth trying if it makes a morning workout feel more pleasant or less hunger-driven. It should not replace food, hydration, sleep, or a training plan that matches your body and goals, says Jo.
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