Why you should sniff (but not eat) chocolate at the gym — and which kind is better

Skip the protein shakes. This unconventional pre-workout might already be in your pantry — and you don’t even have to eat it.

Sports researchers in Malaysia found that offering a whiff of chocolate to people while working out helped them increase their performance during leg exercises.

“We know olfaction is powerfully wired into the brain’s appetite and emotion networks, but surprisingly, no study has systematically looked at the three-way interaction between smell, appetite, and actual resistance exercise capacity,” Dr. Mohamed Nashrudin bin Naharudin, senior author on the study, said in a release.

Training with chocolate

Researchers had 23 young men in their early to mid-20s come in bright and early for a workout before their first meal.

They were divided into three groups and given liquid dark chocolate with 90% cocoa, liquid milk chocolate with 60% cocoa, or water, to smell.

The men were asked to do leg extensions, in which they sat in a chair and lifted up a weighted bar resting on their shin.

After sniffing dark chocolate, they were able to add 18 more reps. Following a whiff of milk chocolate, they did nine more reps.

Interestingly, they didn’t feel like they were exerting themselves more after the chocolate-scented hit. That “is a fascinating psychobiological outcome,” Nashrudin Naharudin said.

They also reported less hunger, more fullness, and less desire to eat after sniffing the dark chocolate. While the milk chocolate smelled more pleasant, it didn’t change their hunger or appetite.

Why does this work?

Feeling full is associated with better athletic performance. What this study suggest is that you don’t actually necessarily have to eat to get that feeling.

“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,” said Nashrudin Naharudin. Meanwhile, his team believes the milk chocolate works by making the workout environment a little bit more pleasant.

They also believe that the smell of food might kickstart the digestive process in anticipation of a meal, mimicking effects of actually eating. And it’s possible that a whiff of foods other than chocolate might have the same effect seen here.

“We don’t think chocolate is entirely unique, though it is a food cue with incredibly strong, universally recognized reward associations,” Nashrudin Naharudin said.

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

How can gym rats use this? Timing eating around a workout can be tricky. You want to be fueled up for a workout, but also you don’t want to feel overfull or have eaten the wrong food that will make you feel sluggish or nauseous.

Many people work out first thing in the morning to avoid this. Research also suggests as many as 38% of athletes opt to work out before eating in the morning because they believe it would help their body composition and performance. Plus, people may be working out while on a intermittent fasting schedule.

Sniffing chocolate (or other foods) could be a useful tool for people like these, who are fueled enough to workout but don’t plan to eat til after.