Chocolate scents may increase gym performance and suppress hunger

Chocolate scents may increase gym performance and suppress hunger

Briefly inhaling the scent of chocolate before and during a weightlifting session may significantly increase the number of repetitions a person can perform without increasing their perceived effort, according to a peer-reviewed study published in Frontiers in Physiology.

Researchers at the University of Malaya in Malaysia conducted the trial with 23 healthy, moderately trained men in their early to mid-20s. To test the interaction between smell, appetite, and exercise capacity, participants fasted for at least 10 hours before their workout. They were divided into three groups and exposed to a scent from a jar for 30 seconds between sets of leg extensions—an exercise where the individual sits in a chair and lifts a weighted bar resting on the shin—at 80% of their maximum weight.

The groups were given either liquid dark chocolate with 90% cocoa, liquid milk chocolate with 60% cocoa, or water as a control. The results showed a marked difference in performance based on the aroma:

A key finding was that participants did not feel they were exerting themselves more despite the increase in volume. "Seeing a substantial increase in repetitions without the athletes feeling like they were exerting themselves any harder is a fascinating psychobiological outcome," Dr. Mohamed Nashrudin bin Naharudin, senior author and assistant professor of sports science at the University of Malaya, via statement.

Different scents, different mechanisms

The study suggests that dark and milk chocolate influence the body through different psychological and physiological paths. Dark chocolate scents were found to suppress appetite by reducing hunger and increasing feelings of fullness before exercise. Researchers believe this happens because the scent acts as a learned cue for a rich, bitter, and satiating food, which essentially tricks the system into an anticipatory state of fullness, according to Dr. Nashrudin bin Naharudin.

In contrast, the 60% cocoa milk chocolate scent did not alter hunger levels or appetite. Instead, the team believes it improved performance by making the workout environment more pleasant, acting as a hedonic reward cue rather than shifting metabolic signals.

The researchers also hypothesized that smelling food may kickstart the digestive process in anticipation of a meal, mimicking the effects of eating. While chocolate was used for the study, the authors noted it may not be unique. They suggested that other appealing and familiar odors linked to satiety could trigger similar performance boosts, provided the person finds the smell appealing or at least not repulsive.

Implications for fasted training

These findings may be particularly useful for athletes who work out before their first meal. Research indicates as many as 38% of athletes choose to exercise in the morning to improve body composition and performance. Others may be following an intermittent fasting schedule. For these individuals, sniffing chocolate could provide a tool to feel fueled and full without the risk of feeling sluggish or nauseous from eating too close to a workout.

However, the research is in its early stages. The sample size was limited to 23 young men, and the researchers noted that no brain activity or blood hormones were measured to confirm the exact physiological process. Further studies involving a more diverse group, including older adults, are needed to determine if these effects are universal.

The study's conclusions on reward associations align with broader research into chocolate's chemistry. According to other reports, the substance phenylethamine (PEA) in chocolate is produced naturally by the brain and can increase serotonin and endorphins. Additionally, theobromine, which is chemically similar to caffeine, is known to stimulate the central nervous system and enhance mood.