Why and How Do UFC Fighters Cut Weight? (Simply Explained)

Jose Aldo UFC 237 bantamweight weigh-in

Are you wondering why and how UFC fighters cut weight?

In this article, we’re going to cover what cutting weight actually means, why UFC fighters need to cut weight, and exactly how they go about doing it.

What Is Cutting Weight UFC?

Cutting weight, or water flushing, is the process of losing water weight in the run-up to weigh-ins the day before a fight. Cutting weight lasts one week and is achieved through the manipulation of the diet, water, and sodium levels.

It’s also the process of dropping weight by cutting body fat leading up to fight week. 

Why Do UFC Fighters Cut Weight?

These are the two reasons UFC fighters cut weight:

  1. To lose as much body fat as possible to get as close to their lean natural weight and be in their best fighting condition
  2. Water weight flushing to get their weigh-in weight as low as possible, in order to fight in divisions much lower than their natural weight; therefore having an advantage in size and power over their opponent after refueling to their natural weight before the fight.

As the UFC is split into weight class divisions, fighters have the ability to fight in whichever division they please but must meet the upper weight limit of said division come weigh-in day, to be able to fight the next day.

The weight class divisions used in the UFC are:

Weight ClassLower Weight LimitUpper Weight Limit
Strawweight (women only)None115 lbs
Flyweight (men and women)115 lbs125 lbs
Bantamweight (men and women)125 lbs135 lbs
Featherweight (men and women)135 lbs145 lbs
Lightweight (men only)145 lbs155 lbs
Welterweight (men only)155 lbs170 lbs
Middleweight (men only)170 lbs185 lbs
Light Heavyweight (men only)185 lbs205 lbs
Heavyweight (men only)205 lbs265 lbs
UFC weight class divisions

As the divisions are initially divided by only 10 lbs, fighters in the lower divisions perfectly executing weight cuts can have the biggest advantages in size and power because every lb of weight counts more at the lower levels as it makes up a larger percentage gain.

For example, if it’s a flyweight fight with an upper weight limit of 125 lbs and one fighter enters the octagon at 150 lbs and the other fighter enters at 145 lbs; the heavier fighter is going to have a significant advantage.

More strength and size for one fighter over another means more powerful striking, grappling, submissions, and energy.

Appearing bigger could also affect a smaller opponent mentally, putting doubt in their mind and making them defensive or tentative.

Also, extra body fat (outside of the heavyweight division) isn’t beneficial to any fighter, especially when you consider there are much larger and leaner fighters cutting body fat and manipulating their weight in order to make the lighter divisions and have a weight advantage.

How Do UFC Fighters Cut Weight?

As mentioned above, fighters have a week to manipulate the scales and flush as much water from their system.

The three techniques used to execute a water flush are:

1. Water and Sodium Manipulation

Water weight flushing means losing as much water weight as possible, and it’s done through the manipulation of water and sodium levels.

The goal is to retain as little water in the body as possible so the fighter comes in as light as can be.

For example, here’s how it might work for a Friday weigh-in:

  • Sunday – 2 gallons of distilled water (9.09 Liters)
  • Monday – 1 gallon of distilled water (4.54 Liters)
  • Tuesday – 1 gallon of distilled water (4.54 Liters)
  • Wednesday – Half a gallon of distilled water (2.27 Liters)
  • Thursday – A quarter gallon of distilled water (1.13 Liters)
  • Friday – No water at all, until the weigh-in

The process has to be done over a 4-6 day period (usually 5) prior to weigh-ins, and the water consumption amounts and timing have to be exact in order to achieve ‘flushing mode’.

This is because the key to achieving flush mode is to drink large amounts of distilled water over the first three days. 

This is vital as it leads to the down-regulation of aldosterone, a hormone that maintains sodium levels in the body.

The down-regulation of aldosterone means sodium is flushed from the body further into the week, as the body now doesn’t notice or react to the low amounts of sodium the fighter will have come weigh in.

If the amounts of water and timing are not followed, the body may not enter flush mode as aldosterone looks to conserve sodium levels, and will defend itself against flushing water and sodium by trying to retain it as much as possible.

As sodium retains water in the body, the flushing of sodium aids in dropping water weight fast. It’s important fighters drink distilled water, as this has sodium and electrolytes removed.

Throughout the week when a fighter begins drinking less water, they’ll still be in flushing mode due to the high consumption of water earlier in the week.

They’ll be urinating lots while drinking less water and this imbalance is the cause of rapid water weight loss and means the body is dehydrating.

2. Carbohydrate and Salt Restriction 

Carbohydrate and salt restriction is the second part of cutting weight and the aim is to consume a low amount of carbohydrates and restrict salt completely in the week before the weigh-in.

Restricting carbohydrates helps fighters achieve a water flush as keeping carbohydrate intake low works to avoid pulling in extra water during their rapid weight loss phase.

This is because each gram of carbohydrate a fighter eats pulls between 2.5-3 grams of water weight into the body.

In the week before weigh-in, UFC fighters consume a maximum of 50 grams (200 calories) per day. This means they’re removing all fruit, starches, and sugars, and only eating vegetables in limited amounts.

They eat leafy vegetables such as spinach and kale, or sometimes they have broccoli. Upon restricting carbohydrates, UFC fighters eat foods high in protein and fat. They will eat foods low on the glycemic index, such as unseasoned meats, eggs, and nuts.

Keeping carbohydrates low also depletes glycogen stores, which is essential for keeping a fighter in flush mode – because glycogen contains water. Therefore, the rapid depletion of glycogen stores at the start of the week triggers the loss of water weight.

Restricting salt aids in rapid weight loss due to the removal of sodium from the body. As sodium causes the body to retain water, having less sodium in the body naturally causes the body to expel water. 

Another reason they’ll want to avoid high levels of sodium in the body is that it can increase the blood volume of fighters, which can cause temporary increases in weight due to bloating.

At the same time as removing sodium, UFC fighters increase their potassium intake. As potassium and sodium are indirectly related, the more potassium a fighter eats, the more sodium they will lose through urine.

To do this, they’ll eat foods such as nuts, leafy greens, beans, lentils, chicken, and salmon.

3. Excessive Sweating

The third way UFC fighters cut weight is through excessive sweating, as it’s another way to lose water and sodium from the body. 

Excessive sweating is usually incorporated on day three or four.

This is because, in order for the body to lose as much water as possible, a UFC fighter must dehydrate and sweat excessively in the 3 days before weigh-in before the body realizes the huge imbalance between water intake and water outflow.

If the body realizes what’s happening, it will start to defend itself against water flushing from its system. If this happens, a fighter will likely not make weight

There are three main ways fighters sweat excessively, these are:

Light cardio With the main aim being to sweat, while simultaneously not draining themselves of too much energy.

A fighter will avoid using heavy weights, as during this time they’re already restricting calories, carbohydrates, and water, and are looking to preserve as much energy as they can. 

Another reason training with heavy weights is avoided during this week is because it causes water retention when the body is trying to repair muscles.

A fighter may use a plastic sweatsuit while doing cardio as a way to trap heat and sweat more.

Saunas and hot baths – Hot baths offer both heat and humidity and the option to fully submerge in water (except the nose). These three factors combined allow for UFC fighters to lose water quickly.

The temperature of the bath has only to be around 100.4 degrees Fahrenheit (38 degrees Celsius) for the eccrine sweat glands to secrete water.

Saunas are another great way for a fighter to sweat excessively, as the higher temperatures cause a fighter’s heart rate to increase, similar to exercise. 

They can also be used for up to 30 minutes at a time, and the heat remains constant, whilst in a bath the temperature drops. Fighters can lose up to 5 lbs of weight after each session.

Towel-wrapping – Here, UFC fighters are wrapped by their coaches in many towels with or without a sweatsuit on, in order to trap heat inside the suit and towels, meaning the sweating process can go on for longer.

A towel wrapping round may last between 20-30 minutes. After this time the sweating will have stopped due to the body’s ability to bring its core temperature down.

If a fighter fears they won’t make weight, they will continuously enter saunas or wrap themselves in towels many times over until their target weight has been met, but overuse will deplete them and leave them feeling very weak.

How Do UFC Fighters Cut Weight (Body Fat)?

UFC fighters also cut weight by slowly cutting body fat. To do this a fighter eats fewer calories during their training camp as a way to achieve a calorie deficit. 

Training camps are usually 8-12 weeks of strict preparation and allow for a fighter to lose 8-12 lbs of body fat in the lead-up to the fight, around a pound of fat per week.

As a pound of fat equates to around 3500 calories, they aim to be in a caloric deficit of 500 calories a day (500 x 7 = 3500).

If they lose weight faster than this during training camp, they’re likely to lose muscle mass and feel very weak before they have to water flush – if they need to.

It’s more efficient for a UFC fighter to restrict carbohydrates during this period, as fewer carbohydrates will result in less glycogen and blood sugar available.

Therefore the body will turn to fat for energy. It also prepares their body for carbohydrate restriction during the upcoming water flushing.

Carb restriction also means a fighter can keep their protein higher while in a caloric deficit, in order to maintain lean muscle mass.

It also allows for a higher percentage of healthy fats in their diet, helping the body absorb vital nutrients, keep blood pressure under control, and protect organs.

This is helpful and important when it comes time to water flush as a fighter’s organs can malfunction because of dehydration.

Despite training camp being the most efficient way for a fighter to slowly lose any excess fat necessary, if they need to fighters may aggressively attempt to cut more body fat during the water flush week.

This is because it compliments their water flush as they’ll be taking in less food, carbs, and salt. In extreme weight-cutting cases, fighters may eat as little as 600 calories and fast for up to 20 hours per day.

How Much Weight Do UFC Fighters Cut?

The amount of weight a UFC fighter cuts varies from fighter to fighter and depends on their walk-around weight and the division they’re attempting to make.

UFC fighters in the past have cut between 25-30 lbs in one week before weigh-in, and others cut less than that in the whole 3-4 months prior to a scheduled fight.

However, the usual weight cut in the final week is around 15-20 lbs because this amount is more easily regained, is less damaging to health, and won’t leave a fighter completely depleted.

On the other hand, 30 lbs can cause a fighter many problems and leave them far from their optimal fighting condition.

Cutting weight is considered the fight before the actual fight, and here are a few examples of some extreme UFC Fighter’s cuts:

Tj Dillashaw (UFC FN:143) cut 29 lbs in 3 months from a weight of 154 lbs to make the flyweight upper weight limit of 125 lbs. Despite doing the cut in an adequate amount of time, TJ was cutting almost 30 lbs from such a low weight – 23% of his total body weight.

It was described as “the most intricately executed and calculated weight cut in history”, but despite this, Dillashaw was left weak and wasn’t himself in the fight against Cejudo; where he was knocked out in the first round.

Conor McGregor (UFC 189) cut 27 lbs in 8 days from 172 lbs to the 145 lb featherweight limit. At the weigh-ins, McGregor looked gaunt and malnourished.

Despite becoming the undisputed featherweight champion, he later vacated the belt and never returned to the weight division; likely because of the extreme weight cuts.

Khabib Nurmagomedov (UFC 209) was as big as 190 lbs before so likely had to cut around 30-35 lbs in a month or two prior to the fight. 

However, the fight was canceled after Khabib was rushed to the hospital in the early morning, suffering from memory problems, kidney pain, and severe dehydration. Doctors have said he almost died to become the first UFC fatality.

Do All UFC Fighters Cut Weight?

No, not all UFC fighters cut weight. Many fighters in the UFC’s heavyweight division will not cut weight and prefer to fight around their natural weight.

Heavyweight fighters are more comfortable with holding body fat because the heavyweight division relies less on speed and precision and more on power and size.

Also, the division has the largest allowed weight range possible, from 205 lbs to 265 lbs. If a fighter feels the extra 20 lbs of weight will help them with power, size, and energy; they’ll opt to stay on the heavier side closer to 265 lbs.

The heavyweights doing a large weight cut are the fighters who prefer having less body fat as it allows them to be lighter, faster, and more precise than their heavier opponents.

UFC heavyweights that walk around at 285 lbs will cut some body fat in the run-up to the fight, and drop around 15-25 lbs of water weight so that they make the limit of 265 lbs. Naturally, they are bigger fighters, so a weight cut is necessary.

Are There Any UFC Weight Cut Rules?

The UFC themselves don’t have any rules regarding weight cutting, but the State Athletic Commissions authorizing the MMA event have the power to enforce their own rules regarding weight cutting.

The only current weight-cut rule was introduced in 2019 by the California State Athletic Commission, which meant a fight would be canceled if either fighter weighed more than 15% above the contracted division’s upper weight limit, on the day of the event.

For example, if a fight was scheduled at welterweight, which has an upper weight limit of 171 lbs for nontitle fights, a fighter isn’t allowed to weigh more than 195.5 lbs (170 x 0.15).

As a result, excessive water weight cutting is prohibited at any MMA event in California. 

The CSAC took this measure to try and prevent unhealthy weight cutting which has caused many MMA fatalities, as well as prevent large differences in weight between athletes. 

It’s likely other Athletic Commissions will follow suit in the future, especially since promotions such as One FC banned weight-cutting in 2015 after the death of their fighter, Yang Jian Bing.

Although the UFC doesn’t have rules regarding weight cutting, they have weigh-in rules meaning a nontitle fight has a maximum weigh-in of 1 lb above the upper weight limit of a division and no extra weight for a title fight.

How Much Weight Do UFC Fighters Put Back on After Weigh-in (And How Do They Do It)?

After a weigh-in, a UFC Fighter puts back on between 10-30 lbs of weight they’ve lost over the past week – depending on how extreme their weight cut has been. 

They aim to gain as much weight as possible and replenish the strength, energy, water, and electrolytes they’ve lost. Only when competing in California do they have to be mindful not to be 15% over their weight division’s upper limit.

They do this 24 hours after Friday weigh-in, by drinking 1 liter (2.2 lbs) of water per hour, as this is the most the body can absorb.

The body will lose 25% of this water as urine, so over 16 hours (8 hours of sleep) a UFC fighter can replenish 12 liters of water or roughly 26.4 lbs – the majority of a fighter’s weight.

Although they’re able to replenish the water they’ve lost in such a short time, fighters may end up heavier than before the water flush and feel just as bad as they did during the weight cut, due to the kidneys not being able to flush the extra water.

Some fighters retain over 80% of the water they drink.

On top of this, they’ll eat as much food as they want, mostly consisting of healthy carbohydrates and protein, as well as some healthy fats.

Carbohydrates help pull water into their muscles, replenish depleted glycogen stores, and give them the energy they need to fight and regain health.

Similar to carbohydrates, fighters add salt to all of their food since sodium helps pull water into the body. 

Along with salt, fighters aim to replenish their electrolytes by drinking coconut water and electrolyte-based sports drinks, which also help fighters consume sugar (carbohydrates).

Electrolyte drinks should be sipped alongside water to prevent drinking over 1 liter of water per hour.

After 24 hours have passed and fighters have had their Saturday weigh-in, they’ll replenish in exactly the same way, but the food portions are much smaller while eaten more often to avoid upsetting their stomach before a fight.


UFC fighters cut weight through water flushing in the week before weigh-ins and by cutting body fat in the three or four months during training camp ahead of a scheduled fight.

Water flushes are executed through water and sodium manipulation, carbohydrate and salt restriction, and excessive sweating. Cutting body fat is a slower process, where fighters aim to lose 1lb of fat per week through a controlled calorie deficit.

The main reason UFC fighters cut weight is to have an advantage in size and power over their opponent, by being naturally much heavier than the weight class division they fight in.

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