Why you should sniff (but not eat) chocolate at the gym

Athletes seeking to push their physical limits during morning gym sessions may find a new, calorie-free advantage inside their pantry. According to recent research published in the journal Frontiers in Physiology, simply inhaling the scent of chocolate before and during resistance training can allow gymgoers to complete significantly more repetitions without any increase in perceived physical exertion.

The study, conducted by researchers at the University of Malaya in Kuala Lumpur, suggests that these olfactory cues may trick the brain into an anticipatory state, potentially serving as a valuable tool for individuals who train in a fasted state, such as those following intermittent fasting routines or those who exercise early in the morning to avoid the discomfort of eating before a workout.

Media additions

The Performance Gap

The trial examined 23 moderately trained men, all in their early to mid-20s, who had fasted for at least 10 hours prior to their gym session. The participants performed sets of leg extensions, with researchers holding a sample of either 90% cocoa dark chocolate, 60% cocoa milk chocolate, or a water-based control under the participants' noses for 30 seconds between each set.

The results indicated a notable disparity in performance based on the aroma provided:

Scent Type	Average Increase in Repetitions
90% Cocoa Dark Chocolate	18 reps
60% Cocoa Milk Chocolate	9 reps
Water (Control)	0 reps

Despite the increase in output, participants reported no change in how hard the exercise felt, a phenomenon that Forbes and other outlets describe as a "fascinating psychobiological outcome." Dr. Mohamed Nashrudin bin Naharudin, the study's senior author, noted that this finding suggests the benefits arise from psychological shifts rather than purely metabolic ones.

How Smell Influences the Brain

The research team proposes that dark and milk chocolate function through distinct neurological pathways. The scent of 90% dark chocolate appears to act as a learned cue for a rich, satiating food, effectively triggering the body's digestive system to enter an anticipatory state of fullness. As reported by Earth, this "cephalic phase" can involve the release of saliva and hormones in preparation for a meal, which may help mitigate hunger during a workout.

Conversely, the 60% milk chocolate aroma does not suppress hunger signals. Instead, researchers believe it functions as a hedonic reward. By creating a more pleasant sensory environment, the milk chocolate scent motivates athletes to continue their sets through the influence of enjoyment rather than satiety.

According to the New York Post, the study suggests that chocolate is likely not unique in this regard. The primary requirement for a similar performance boost may simply be that the scent is familiar and appealing to the individual. If the odor is repulsive, it is unlikely to generate the psychological shift necessary to increase training volume.

Limitations and Future Considerations

While the findings offer a low-cost, convenient strategy for gymgoers, experts caution that the research remains in its early stages. The study was restricted to a small cohort of young men and focused exclusively on leg extensions. As noted by Starts at 60, further research is required to determine if these effects are consistent across different demographics, including women and older adults, or if they hold true for broader categories of resistance training.

Furthermore, the study did not measure specific blood hormones or brain activity to confirm the physiological mechanisms at work. Because of this, the researchers emphasize that their conclusions regarding the brain's role in this performance boost remain based on inference.

For those interested in experimenting with this method, health experts generally recommend consulting with a GP or accredited exercise physiologist before making significant changes to training routines.