Sniffing chocolate, especially dark chocolate, could be the key to boosting gym performance, a new study suggests. Researchers from the University of Malaya in Kuala Lumpur found that smelling dark chocolate led to people performing more leg extensions while also curbing feelings of hunger.
Study Design and Methodology
Published in the journal Frontiers In Physiology, the study involved 23 healthy men in their early to mid-20s, divided into three groups. Each group sniffed one of three odour samples: liquified dark chocolate containing 90% cocoa, liquified milk chocolate containing 60% cocoa, or a water sample as a control. All participants had not eaten for the previous 10 hours.
They performed leg extensions, a seated exercise where the lower legs are extended to lift a weight. Performance was assessed before and during training, with levels of hunger, fullness, desire to eat, and plans to eat measured beforehand. During sets, hunger and desire to eat were also measured 30 seconds after sniffing the odour sample.
Key Findings: Dark Chocolate Leads to More Repetitions
Results showed that, compared to the water control and milk chocolate, sniffing dark chocolate consistently led to less hunger, reduced desire and intention to eat, and greater fullness before exercise. Even milk chocolate sniffers saw beneficial performance results. Across both chocolate types, participants did not feel they were training harder but managed more repetitions.
Senior author Dr Mohamed Nashrudin bin Naharudin said: “Sniffing a 90% dark chocolate odour added about 18 more repetitions to participants’ leg extensions while a 60% milk chocolate odour added about nine repetitions compared to the water control.” He added: “Exposing moderately trained men to chocolate odours right before and between sets of resistance exercise significantly increased their overall training volume without increasing their perceived exertion. Seeing a substantial increase in repetitions without the athletes feeling like they were exerting themselves any harder is a fascinating psychobiological outcome.”
Psychological Mechanisms Behind the Effect
The researchers suggest that changes in appetite perception may relate to learned associations from childhood. Anticipating a food might have similar effects to actually eating it. Dr Nashrudin bin Naharudin explained: “The dark chocolate scent serves as a learned cue for a rich, bitter and highly satiating food, which essentially tricks the system into an anticipatory state of fullness. Conversely, the sweeter milk chocolate scent acts more like a hedonic reward cue, enhancing training volume by creating a highly pleasant sensory environment rather than by shifting basic metabolic hunger signals.”
Future Research and Implications
Although not yet tested, the team believes other appealing foods could also have an effect. However, they caution that more work is needed, including studies with larger samples.
