Want to get more out of your workout? The unlikely treat that could help

Saturday, 11 July 2026

Researchers at the University of Malaya found that smelling dark chocolate before strength training helped participants complete 18 more repetitions without increased effort.

The study involved 23 healthy men who performed leg extensions after fasting for 10 hours while exposed to different chocolate scents.

Dark chocolate with 90% cocoa proved more effective than milk chocolate with 60% cocoa for boosting exercise performance through smell.

Looking for an edge on leg day? Researchers in Malaysia say the answer could be as simple as taking a quick whiff of dark chocolate.

A new study has found participants who smelled high-cocoa dark chocolate before and during a strength-training session felt less hungry, felt fuller and managed more repetitions.

'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,' said Dr Mohamed Nashrudin bin Naharudin, an assistant professor at the Faculty of Sports and Exercise Science at the University of Malaya.

'Seeing a substantial increase in repetitions without the athletes feeling like they were exerting themselves any harder is a fascinating psychobiological outcome.'

Researchers also tested milk chocolate, but the effect was less pronounced.

The Frontiers in Physiology study involved 23 healthy, moderately trained men in their early to mid-20s. After fasting for at least 10 hours, they performed leg extensions while being exposed to one of three odours: liquefied dark chocolate containing 90% cocoa, liquefied milk chocolate containing 60% cocoa, or water as a control.

Those who sniffed the dark chocolate completed about 18 more repetitions than the control group, while those exposed to the milk chocolate scent managed about nine extra repetitions than the control group.

Nashrudin Naharudin said no previous study had systematically examined the interaction between smell, appetite and resistance exercise performance.

The dark chocolate aroma '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.'

Associate Professor Mei Peng, from the University of Otago's Sensory Neuroscience and Nutrition Lab, said she was surprised by the size of the effect, but not by the idea that smell could influence behaviour.

'Our sense of smell is very powerful,' she said.

'It is closely related to ghrelin, which is a key hormone that makes us feel hungry, so it is definitely one of the pathways that could influence hunger.'

Peng said she was intrigued to see smell being studied in relation to exercise rather than food.

'It's about energy expenditure rather than energy intake. I think that's very interesting.'

She was a co-author on a recent study exploring how hunger influences our ability to imagine food and whether those mental images become more vivid depending on our metabolic state.

The researchers in the Malaysian study acknowledged several limitations, including the small sample size, a lack of diversity and the fact some participants smelled odourless water, which may have tipped them off that they were in the control group.

Only chocolate was used and Nashrudin Naharudin would be interested into further research using other food groups.

“We don’t think chocolate is entirely unique, though it is a food cue with incredibly strong, universally recognised reward associations.

“A person likely needs to find the odour familiar and appealing – or at least not repulsive – to trigger the psychological shift in appetite that’s needed to see a performance boost.”

Peng says despite the limitations, the study is still a good start.

'From my point of view, it's great to see people becoming more aware of smell and how much it influences our behaviour in so many different ways.'