Issue 226

December 2025

Ray Klerck reviews the latest performance research to uncover the calorie-free strategy fighters can use when every calorie counts.

As a weight-class sport, MMA requires almost every fighter to be a calorie accountant. This means you might be looking for ways to keep your engine running without pushing the scales north. However, MMA athletes seem to be routinely getting on the wrong side of the math. A December 2025 systematic review of combat sports athletes found most fighters already run their engines below recommended energy and carbohydrate intakes, averaging just 33 calories per kilo per day, even before weight cuts begin. For a lightweight, that’s barely 2,300 calories. For a light heavyweight, just over 3,000. During fight camps, those numbers fall further, often at the expense of lean mass rather than fat. This may explain why fighters are constantly hunting for ways to feel fast, sharp, and explosive without adding a single gram to the scale. Fortunately, we’ve unearthed a loophole for your pie hole. November 2025 research in the Journal of the International Society of Sports Nutrition found that your brain doesn’t need to eat carbs to act like it’s just received an energy shot. All it needs is the taste. They discovered that rinsing your mouth with carbohydrates, not swallowing, flicks on the parts of your brain needed to get you to exercise. The trick is more neurological than nutritional, which might be gold during weigh-ins or high-volume camp days. What follows is an explanation of why this unusual rinsing trick might become an innovative nutrition strategy where your brain gets an energy deposit, the scales see no transaction, and your calorie ledger stays squeaky clean.  

HOW THE SCIENCE WORKS

Your mouth acts like a snitch to your nervous system because from the moment a carb touches your tongue, a specialized set of receptors fires off messages to your brain’s reward and motor control centers. On average, athletes got a 2-3% performance bump just from swishing a carb drink around their mouth like they were tasting a Shiraz they couldn’t afford. At this stage, you haven’t digested anything or eaten a single calorie, but your brain anticipates that cavalry armed with glycogen is on the way, because who in their right mind puts things in their mouth and doesn’t swallow? This cerebral sleight of hand convinces your muscles to move more because fuel is on the way. Except it isn’t, thanks to a nutritional Jedi mind trick that delivers a 4% increase in aerobic endurance, which can last 1–10 minutes. It’s not going to make you superhuman, but it does give you a free performance boost you didn’t really earn. 

FIGHT CAMP SORCERY

If it sounds more like Harry Potter than fight science, this isn’t a one-off revelation. The idea goes back to 2009, when researchers at the University of Birmingham had cyclists perform the carb rinse-and-spit switcheroo and saw a 2-3% improvement, which was one of the first entries in the long line of ‘your brain is an easily tricked idiot' findings. It seems to fall for these bait-and-swap moves a fair bit, and it’s not always through the mouth. A paper in the Journal of Environmental Psychology found that just being in a room that smelled like coffee made people perform better on analytical reasoning tasks, purely because the scent pumped up their expectations about feeling alert and more dialed in. They didn’t even sip and spit. They just woke up and smelled the coffee. If you brew this with a sprinkling of the mouth-rinse data, you get the picture that your nervous system is constantly overreacting to hints and suggestions. We can use this to pull the chair out just as it’s about to sit down, which fighters can exploit to get that energy kick minus the calories. 

HOW TO REVIVE THE ENERGY

The how-to part is pretty simple, but if you want it fed to you like peeled grapes to a Roman emperor, then this is the right way to do it. Mix up a simple carb drink made with maltodextrin, as the researchers did. This stuff is almost pure glucose, so it digests very quickly and isn't something anyone should ever drink, especially someone on a weight cut. Add roughly a heaped tablespoon of this cheap ingredient to a cup of water and stir vigorously. Now take a small sip, not a hero’s gulp that’s big enough to baptize a toddler. Swish it around your mouth for 10 seconds, making sure that it actually hits your tongue receptors and isn’t just missing everything completely. You should taste it, then spit it out with confidence. Do not swallow, as that ruins all the magic. You should feel it almost immediately, and since it doesn’t add any weight to your stomach, you can do it between rounds, during a VO2 Max hill sprint session, or on those low-calorie days when your soul quietly packs a suitcase and tries to leave mid-training session. The same effect might work almost as well with a run-of-the-mill Gatorade, which is often the easiest option. Just remember to brush or rinse with plain water afterwards, because those high-sugar, acidic sports drinks are among the worst things you can expose your teeth to. MMA always has a problem with grills, so there’s no need to add to it. 

SPITTING UP EFFICIENCY

If you want to squeeze every last bit of wizardry from this trick, then timing is everything. Mouth rinsing will work best when you’re feeling like you’re running low, so deploy it strategically when your body starts submitting formal complaints about the lack of calories. When you’re doing the serious conditioning stuff, then your brain will be desperate enough to fall for the bluff. It will also shine as a power-up before high-intensity bursts like VO2 Max intervals, hill sprints, or sparring. It’s something we may start seeing more of between rounds because your brain believes there is fuel coming in. Fight week will always be where the magic happens because you need energy, but are dieting, so you probably feel like you’re operating with the emotional bandwidth of a wet tissue. A quick rinse will give you the carb perk without the scale jumping higher. Just don’t use it on easy days or during technical sessions, because your brain may start to reduce its effect. In a sport with sometimes questionable ideas, this might be the only one where spitting might make you fitter and faster.