A new study out of the University of Malaya suggests one of the simplest performance tweaks for a fasted workout might be sitting in your pantry: the smell of chocolate.
Published September 15 in Frontiers in Physiology, the study had 23 moderately trained men complete a randomized, double-blind trial in which they performed leg extensions after smelling either 90% dark chocolate, 60% milk chocolate or a water-based control, having fasted for at least 10 hours beforehand. Men exposed to the dark chocolate aroma completed about 18 more repetitions than the control group, roughly the equivalent of an extra set, while those who smelled milk chocolate managed about nine more.
Same effort, more reps
Crucially, ScienceDaily's summary of the findings noted that neither chocolate condition made the workout feel harder, even as participants pushed through more volume. Dark chocolate's scent was also linked to lower reported hunger and greater fullness, while milk chocolate's aroma was rated more pleasant without changing appetite in the same way.
Exposing moderately trained men to chocolate odors right before and between sets of resistance exercise significantly increased their overall training volume without increasing their perceived exertion.
Dr. Mohamed Nashrudin bin Naharudin, University of Malaya
The researchers, whose work was also covered by Healthline, theorize that familiar food smells trigger anticipatory brain responses tied to learned associations — dark chocolate's scent cueing a rich, satiating food that suppresses appetite, and milk chocolate's scent acting more as a pleasant reward that keeps people motivated through extra sets.
The team cautioned the sample was small and limited to young men, so the effect hasn't been confirmed in women or older or untrained populations, and the study didn't measure hormones or brain activity directly. Still, the authors suggested a whiff of chocolate before a fasted workout could be a low-cost, low-effort way to squeeze a bit more out of a session, particularly for anyone who trains before breakfast.
