Perform More with the Perfect Flavor (#425)

Summary: Can the taste we experience when we put something in our mouth enhance our performance? It's an exciting question we're exploring right now. Based on a review article — Can taste be ergogenic? — along with some insights from other articles, we dive into what research says about flavors like sweet, bitter, chili/capsaicin, and menthol, and why some effects seem to be more about the brain than energy or “real” cooling. The conclusion is that certain tastes and oral stimuli can have a performance-enhancing effect in specific situations, but the effect depends on context, dose, and sometimes even how you perceive (or don't perceive) the taste.

First, let's specify what taste really is. Taste is an experience and a function that partly saves us from ingesting toxic substances by determining what we swallow and what we instinctively spit out. The taste function can also detect if a food is rich in energy, if it needs to be processed more before swallowing, and if we like what we are eating or not.

Taste isn't confined to just the oral cavity. In everyday life and even in much research, there's often a distinction between taste (gustation) and flavor (the overall experience that also includes scent, trigeminal sensations, and sometimes sight). It's often said that we eat with all our senses — and it's true. Taste is also a purely chemical system where reactions can occur even if we've lost our sense of taste or smell. Even people with impaired taste or smell (for example due to COVID-19) often spit out bitter or potentially toxic substances without having perceived a clear taste. This involves our more primal system that reacts almost without our conscious interpretation of what has entered our mouth.

There are now several flavors that seem performance-enhancing in different situations. We will go through them now — and also discuss the placebo effect of various tastes.

Here, you'll find the most common flavors in sports nutrition. These are primarily carbohydrate-based products with a high glycemic index and sweet flavors available on the market.

It's well-known that mouth rinse can boost performance. All it takes is to have carbs in your mouth and then spit them out. According to the "Central Governor" theory, the brain identifies the energy content in the mouth via taste buds and releases some restrictions, allowing you to push a bit harder. Read more about mouth rinse in our previous article here.

It's important to note that experiments with non-sweetened carbohydrates like maltodextrin have shown performance-enhancing effects. However, studies with sweeteners showed no effect. So, the sweetness itself isn't critical; what you take in must contain energy. Researchers aren't exactly sure how it works, but the hypothesis is that it has something to do with the bonds in the carbohydrate chains. Our body is pretty cool anyway 😉

Bitter flavors often activate the same areas of the brain as sweet flavors. In several studies, participants who were given bitter, calorie-free solutions performed better. In a randomized study, participants were given a bitter solution with quinine once, a sweet solution (aspartame-sweetened) once, and just water once; all drinks were calorie-free, and participants acted as their own control group. In a 30-second sprint, participants performed 2.4% better than with aspartame and 3.9% better than with water.

In that study, all drinks were kept in the mouth for 10 seconds and then swallowed. In another study, an even stronger bitter drink was used, but the participants did not swallow it — and no performance boost was observed. The hypothesis is that many receptors for bitter flavors are located in the upper part of the esophagus, so the drink needs to be swallowed to have an effect.

Summary for sweet and bitter: for both flavors, you don't need to consciously perceive the taste. Activation of brain regions that allow us to push a little harder doesn't depend on us experiencing sweet or bitter on the tongue.

So far, only four studies have investigated the ergogenic properties of capsaicin intake or mouth rinse. Three studies examined the effect of an acute supplement of 12 mg capsaicin 45 minutes before a 1500-meter running test. Another study used the same dose and tested four sets of squats to failure at 70% 1RM (one-repetition maximum), and a third study ran 15/15 intervals at 120% VO2peak (peak oxygen uptake) on a treadmill to exhaustion.

Capsaicin supplementation improved performance in the 1500-meter time-trial by 1.6% (about 5 seconds) compared to placebo.

In study two, participants lifted a total of 19% more weight (3919 kg vs 3179 kg), but with a wide range of results (over 1000 kg), the figures and conclusion were a bit scattered.

In the third study, where time to exhaustion was measured, participants on average lasted 12% longer (about 3 minutes) with capsaicin than with placebo. Rate of Perceived Exertion (RPE) was also significantly lower, although no differences in blood lactate were shown.

Capsaicin was consumed in capsule form, so participants did not taste it in their mouths. As discussed earlier, "taste" is perceived in other places in the body as well. One reason for capsaicin's performance-enhancing effect might be that capsaicin has a certain analgesic (pain-relieving) effect, which lowers RPE and allows us to push a little extra. Capsaicin also increases fat oxidation, which can be significant — though probably not in these relatively short and intense tests (6–25 minutes).

For more info on capsaicin and its potential performance-enhancing and anti-cramp effect, read here and here.

Menthol and mint stimulate several receptors that are abundantly present along the trigeminal nerve and evoke a sensation of coolness — at least in younger people. A study showed that a younger group (around 20 years old) clearly experienced the cooling effect of menthol, while an older group (75 years) did not. In other words, menthol's icy sensation might diminish with age, and higher doses may then be required.

In studies, the dosages are usually around 30 mg per kg of body weight. Effects observed include increased time to exhaustion and a more "pleasant" or comfortable feeling during performance in heat. However, the sensation of being cooler is false — the body is not physically cooler; we simply trick the brain. It has also been observed that consuming menthol suppresses thirst. This can be beneficial if you are in fluid balance or at least not so dehydrated that performance is affected. In that case, it can help block the thirst sensation that might otherwise hinder performance and be irritating.

But menthol can just as easily be very bad if you really should drink and risk impaired performance due to dehydration.

For more info on menthol and its performance-enhancing effect in heat, read here.

We covered this in our article on ultrarunning a couple of weeks ago. Eventually, you become very tired of a specific flavor — it can be the general taste of sweetness (regardless of flavor profile) or a very specific taste (for example, cola, blueberry, or lemon). When this happens, it becomes difficult to consume energy, and the risk of exhaustion, bonking, or general fatigue increases.

One way to get around this is to work with variation in basic flavors. If you have a lot of sweet gels or sports drink with you, it can be good to break it up with something minty, strong, or bitter. A homemade menthol shot can be absolutely phenomenal in these situations (provided you're not already too cold).

Listen to your body, plan the flavors in your nutrition schedule, and have a plan B in your pocket — it's easier to avoid the headache of flavor fatigue than to fend it off once it's there.