MMA is a competitive combat/fighting sport and strives for sportsmanship-like conduct doing its best to have compelling fighters that don’t cheat. Weight cutting is a subtle way to gain an advantage over your opponent.
To understand why fighters do it, you must first understand what MMA weight classes are. Fighters are categorized by weight classes in mixed martial arts and many other combat sports like boxing. To make their planned weight classes for competitions, fighters often cut weight, a practice that involves temporarily shedding pounds in the days leading up to the official weigh-in. After the weigh-in, they’ll rehydrate and replenish to get back to their natural, fighting-fit weight.
Weight classes are divisions that fighters are placed into when competing against opponents with similar body types and weights, so there are no competitive advantages. Say a fighter who weighs 160lbs is matched with another fighter who weighs 190lbs; the 190lb fighter is bigger and stronger than the 160lb fighter, thus giving them the advantage during the fight. This is why having a weight division is essential.
Weight divisions and cutting go hand in hand. Weight cutting is when you lose your natural walking weight for a few days to get paired with fighters in a lower-weight division than your natural weight. There are fighter weigh-ins that determine in what division you’ll be placed.
Weight cutting is the practice of fast weight loss prior to a sporting competition. It most frequently happens in order to qualify for a lower weight class or to meet the maximum weight limit in their weight class if one exists (usually in combat sports or rowing, where weight is a significant advantage) or in sports where it is advantageous to weigh as little as possible (most notably equestrian sports).
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In very simple terms, weight cutting is the process of decreasing body weight during an acute period of time. However, prior to any weight cut (the final seven days prior to competition) starting, the manipulation of body composition is best done gradually over time. Essentially, before the final week of training camp and before any acute weight loss occurs, the goal is to reduce fat mass while maintaining or even gaining lean mass (muscle).
When you cut weight you have a competitive advantage, meaning you have a larger body mass than your opponents. This is the most important distinction here.
In MMA, one of the reasons that they cut so much weight is because of that advantage: the ability to impose their weight on their opponents. And this is why also you'll see in wrestling that the bigger, the bigger man usually is going to win assuming the skills are the same.
Another reason to cut weight is if a fighter is in between weight classes or they're specifically undersized for the higher one. So if a fighter is undersized for a higher weight class, they genuinely want to go to the lower weight class where they will be more situated to kind of have a better outcome.
UFC fighters lose up to 20 pounds in five days leading to weigh-in for a fight.
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How UFC Fighters Lose 25 Pounds Over Night
The Science Behind Weight Cutting
The main way fighters cut so much weight so fast is by dehydrating themselves throughout their cut. Water makes up 60% of our body weight, so cutting out water is essential in the process of losing weight quickly and temporarily. Fighters also avoid carbs and salts to ensure the best results. On average, fighters typically cut 15-20lbs.
Weight cutting isn’t like normal weight loss. Fighters don’t lose fat or muscle-they lose water. Roughly 50 to 70 percent of your body is water. That water is necessary for every cell, tissue, and organ to function. If you weigh 150 pounds, 75 to 105 pounds of your weight is water.
But the amount of water in your body is constantly changing. It depends on:
- What you eat and drink.
- How active you are.
- How you sleep.
Fighters are categorized by weight classes in mixed martial arts and many other combat sports like boxing. To make their planned weight classes for competitions, fighters often cut weight, a practice that involves temporarily shedding pounds in the days leading up to the official weigh-in. After the weigh-in, they’ll rehydrate and replenish to get back to their natural, fighting-fit weight.
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Picture this: fighters wrapped in layers of clothing, trash bags (yes, trash bags), or sauna suits, sweating it out in an actual sauna. While saunas can help shed water weight, spending extended periods can be risky healthwise. Some fighters opt for hot baths infused with Epsom salt, which can help draw out moisture from their bodies.
Some MMA fighters may limit water intake in the days leading up to their competitions, making them as dry as British humor. This process, called “water loading,” involves drinking lots of water (we’re talking more than your recommended eight glasses a day) and then suddenly cutting it off. The body, tricked into thinking there’s a water surplus, keeps expelling it. Some MMA fighters enjoy engaging in light cardio exercises like going at a moderate rate on an exercise bike while wearing a sauna suit.
In the week prior to weigh-in, the current literature shows fighters commonly lose mass which is either greater than or equal to 10% of their own body weight. For example, some fighters who weigh in at 70kg might lose 7kg in the final week before weigh-in. However, as mentioned, this is very individual-specific, and while there is no single ‘ideal’ acute weight loss target, research suggests that under some conditions, a loss of 5-8% body mass may be possible, with an acceptably small impact on health and performance.
There are many ways in which body mass can be reduced during the final few days and hours prior to making the weight. A combination of the following methods can all work together to see a drop of between 1-8% of body weight prior to weigh-in.
FIGURE 2. There are many ways in which body mass can be reduced during the final few days and hours prior to making the weight.
In short, fighters don’t lose fat or muscle in the process. They lose water. They do this by leveraging a tactical timeline that involves manipulating their water and diet to purge water from their bodies.
The Water Formula
Because cutting is entirely about losing water, fighters can’t drink as much as they’d like. The formula is: the fighter’s body weight in kilograms times point one. So, for example, a 180-pound/82-kilo fighter’s formula would be: 82 x 0.1 = 8.2. Hence, that fighter would drink roughly eight liters of water a day.
The Salt Formula
Sodium helps our muscles and brain function. It’s necessary for survival. But it also helps you retain water. That’s good for hydration, but it can work against you if you’re trying to shed water weight.
Instead, Minton cuts the fighter’s sodium to just below 1,000 milligrams. That’s enough of a drop to stimulate water loss, but it also prevents issues that come from trying to cut salt altogether. For context, the average person consumes ~3,000 to 4,000 milligrams of sodium each day. (Fun fact: humans only need about 300mg a day to survive.)
Train Easier
Fighters have been training hard in the months leading up to the fight. But at this point, as we say in Tennessee, the hay is already in the barn. We’re not going to improve a fighter’s fitness the week before the fight. Training hard during the intense cut is only going to burn them out for fight day.
Eat More Fat and Fewer Carbs
As a fighter trains hard in the months leading to a fight, their diet is mostly carbohydrates (about 60 percent). But carbs cause your body to retain more water. One study found that “each gram of glycogen (carbs) is stored in human muscle with at least three grams of water.”
The fighters start eating 60 percent of their calories from fat. Roughly 35 percent come from protein and only about 5 percent come from carbs. Their body purges water even though they’re eating the same amount of calories.
Remove Fiber
Fighters used to eat lots of vegetables before fights. The idea was that vegetables would fill them up but not add many calories. That was true, but fiber also acts like a sponge soaking up water.
So we eliminate fiber from the fighter’s diet. This lowers the bulk in their stomach. It can take up to three days for food to pass completely through their system. By lowering the bulk in their stomach, fighters will lose around two percent of their total body weight. So if you have a 200-pound fighter, they're going to lose about four pounds that week purely by dropping their fiber.
These 24 hours before weigh-in are critical. The goal is to dry up the sponge. A fighter still may have five or six pounds to lose before the weigh-in.
Reduce Water Even More
Now we change the water formula so it’s their bodyweight in kilograms times 0.01, which is usually about 20 to 30 ounces for the entire day. But the fighter is still decently hydrated because we haven’t completely cut out sodium. We haven’t completely cut out carbs. And we didn’t train hard all week.
Sweat Out the Remaining Weight
People sweat differently. So Minton conducts sweat rate testing during training camp and records all of his fighters’ sweat rates. This data allows him to get tactical by having them sweat out the remaining water by sitting in a hot tub.
Prioritize Sleep
Fighters stop drinking water Thursday night. Thursday night I usually give the fighters ice cream or frozen yogurt. The fighters often worry about the carbs. But at this point we’re not drinking any water. So those carbs don’t have water to cling to and aren’t going to cause water retention. And that ice cream is a huge psychological boost-cutting is miserable. And the carbs also help them sleep better.
Sleep during this stage is critical-we lose a lot of water during sleep, and adequate sleep helps them perform better during the fight.
Friday morning before weigh-in is simple: The fighter gets no food or water. They’ve done the work and met their goal.
Rehydrating and Replenishing
It’s time to rehydrate after successfully gaining weight and resisting the urge to dive into the nearest buffet. MMA fighters usually guzzle water, sports drinks, and baby food to replenish all the water and electrolytes they’ve lost. Fighters also munch on potassium-rich foods like bananas and potatoes. Why, you ask? Potassium helps with muscle function and can prevent cramps during a fight.
After the weigh-in, fighters are thirsty and hungry. They think they can just eat and drink whatever now. But we need to rehydrate and feed them slowly so they don’t get stomach issues.
Drink First
For the first hour, fighters slowly sip about three liters of different electrolyte drinks, starting with drinks similar to no-sugar Gatorade and ending with full-sugar Gatorade.
Eat Slow and Smart
After the fighter is hydrated and starts processing through those liquids, we introduce some foods. They start with candy. At this point we’re just trying to load sugar slow and steady so we don’t get stomach issues. For example, gummy bears because they’re high in carbs and easily digestible. Then he moves into dried fruits and bread with jelly.
After two hours, the fighter eats their first real meal. It’s usually low in fat because fat slows the absorption of sugars. So something like sushi or pasta.
Their eating shifts back to being like it was in the months of preparation: healthy but higher in carbs.
The morning of the fight, we splurge a bit. I’ll be like, hey, let’s go get some pancakes or french toast. That gives fighters a psychological boost and lots of calories before (but not too close to) the fight.
The fighters have their final meal five hours before the fight, then some high-carb, low-fiber snacks until they walk out. We want the food broken down and not heavy in their stomach. It’s usually lean meat and rice.
When enter the octagon, they’re 10 to 20 pounds heavier than they were Friday morning.
The Dangers of Weight Cutting
Cutting is hazardous and could significantly damage the body if done incorrectly. Fighters have access to all kinds of nutrition and medical professionals to ensure they are doing it safely. Cutting weight doesn’t mean starving yourself and not drinking water; this approach can lead to organ failure or even death.
Weight cutting done incorrectly can result in serious consequences, and in some devastating situations, even death.
Improper weight cutting can result in dehydration, kidney damage, and severe electrolyte imbalances. One of the primary concerns in rapid weight-cutting is severe dehydration. Fighters often use methods like saunas, sweat suits, and diuretics to shed water weight.
Severe dehydration can impact nearly every system in the body, putting additional strain on the kidneys, potentially leading to kidney issues. Additionally, rapid weight loss can cause electrolyte imbalances. Electrolytes such as potassium, sodium, and calcium play a crucial role in bodily functions like muscle contractions and nerve function. Dehydration reduces the fluid surrounding the brain, diminishing its protective cushioning.
Beyond these acute risks, repeated cycles of rapid weight loss and gain can have long-term effects on metabolism, cardiac health, and overall physiological well-being.
Throughout the entire MMA history, extreme weight-cutting has resulted in two untimely deaths. Since then, UFC fighters have been taking weight cuts more seriously.
In December 2015, 21-year-old Chinese mixed martial artist Yang Jian Bing died due to dehydration when weight-cutting for a fight put on by Singapore-based ONE Championship.