A study published in the journal Frontiers in Physiology found that inhaling the aroma of chocolate before and during strength training can help increase the number of repetitions performed without causing additional fatigue.

Experiment Procedure

The study involved 23 healthy men aged 20 to 25 with moderate physical fitness. Participants were divided into three groups, each inhaling one of three aromas: liquid dark chocolate with 90% cocoa, liquid milk chocolate with 60% cocoa, or water (control group). Before the workout, participants fasted for at least 10 hours. They then performed leg extensions—an exercise where a seated person straightens their legs against resistance.

Measured Parameters

Before and during the workout, researchers recorded participants’ levels of hunger, satiety, desire, and intention to eat. After each 30-second exposure to the aroma, they also measured hunger and the desire to eat.

Effects of Aromas

The aroma of dark chocolate was associated with reduced feelings of hunger, decreased desire and intention to eat, and a greater sense of fullness compared to milk chocolate and water. Participants rated the milk chocolate aroma as more pleasant, but it did not significantly affect appetite or hunger.

Inhaling the aroma of dark chocolate increased the number of leg extension repetitions by about 18 compared to the control group, while the milk chocolate aroma led to an increase of 9 repetitions.

Possible Mechanisms

The researchers suggest that these effects may be linked to associations formed in childhood between certain smells and eating. Over time, such aromas become signals that trigger the body’s expectation of satiety, which can influence subjective feelings of fullness and energy even before actual food intake.

Study Limitations

The authors note that the biological mechanisms underlying these effects remain unclear, as no measurements of hormonal levels or brain activity were conducted. Additionally, the intensity of the aromas may have varied, and using water as a control allowed participants to realize they were in the control group. The study was small and included only young men with moderate fitness, so further research involving different groups is needed for broader conclusions.

Outlook

It remains uncertain whether the effect is unique to chocolate or if similar reactions could be triggered by other familiar foods associated with post-meal satiety. The researchers believe that for a psychological shift in appetite that enhances workout effectiveness, the aroma should be familiar and pleasant, or at least not cause aversion.