Coach’s Corner
How To Lose 20–30 Pounds In 5 Days: The Extreme Weight Cutting and Rehydration Secrets of UFC Fighters
By Nate Green • Updated September 24, 2025
Caution: This piece explores how fighters manipulate weight for competition. It is not a recommendation. Extreme dehydration and rapid shifts in water/sodium can be dangerous without medical supervision. For everyday athletes and clients, prioritize sustainable, brand-aligned strategies that protect performance, cognition, and recovery.
The following is a guest post by Nate Green, who works with Dr. John Berardi, nutritional advisor to athletes like UFC champion Georges St. Pierre (GSP). We do not recommending you follow these extreme water weight cutting strategies for any reason at all, even for the reason described in the article, but there are a few take aways:
When you sacrifice nutrition and diet for quick weight loss, not just water cutting or water only diets (WTF) for weight loss, you hurt your health, fitness, performance and health. In ANY amount, ANY reason.
If only Nate knew about the benefits of FUNDAMINOS for preserving muscle, appetite satiation, and strength, he may have been able to also prevent losing some of those performance gains while temporarily cutting his weight. This is also a big secret of elite athletes, targeted amino acids supplementation!
Remember any type of water loss hurt performance, and that supplementing with more carbs during long extended periods of effort actually helps you stay more hydrated and have better energy. Once again, better looks and lower weight and performance don't correlate.
When you are looking to gain or lose weight HEALTHILY, you should focus on the nutrient quality of what you are eating to fuel your cells. Wearing a CGM, especially if you carb loading/refueling frequently, is also a great way to make sure you aren't hurting spiking your blood sugar and hurting your health and ideal weight.
Empty simple carbs and sugars don't just hold on water weight, they get converted into sugar and stored as extra weight into the fat cells. This is more important than any random weight loss tip. Are you fat or overweight because you eat unhealthy foods? NOT REALLY. It's because you eat foods that SPIKE your blood sugar that converted into fat and/or eat too many calories and toxic foods.
No matter what diet or extreme physical experiment your doing to your body, you can never go wrong with eating more protein, especially for breakfast!
Cautionary Note on Part 1
Mixed Martial Arts (MMA) fighters put it all out in the open for the world to see: they kick, punch, laugh, cry, and bleed in front of thousands of arena fans and millions more watching at home.
But even if you’re a hardcore fan who knows all the stats, there’s something behind the scenes that you’ve probably never seen in full: world-class weight manipulation…
Done right, it can significantly increase a fighter’s chances of winning. An athlete will artificially lower his weight for pre-fight weigh-ins, then show up to the actual fight 10, 20, or even 30 pounds heavier than his opponent. It’s a game changer.
Done wrong, it can make even the toughest guy lose his edge… and probably the fight. There’s serious risk of organ failure if done haphazardly.
Even though boxers and wrestlers have been manipulating weight in this fashion for decades, it has the air of illicit activity. And though it’s legal in MMA competition, you should never try this at home or without medical supervision. Excessive dehydration can kill you. “Cutting weight” has no place in real-world dieting or behavior.
This is NOT an article on sustainable weight loss or healthy living. Rather, it’s a fascinating look at how far athletes and scientists will go to manipulate the human body for competitive advantage.
Here’s how it works…
Enter Nate
Imagine this: It’s Saturday night and you’re a top-ranked MMA fighter who just stepped into the cage to fight for the 170-pound Welterweight Championship.
Question: How much do you weigh?
The answer may seem obvious: 170 pounds, right? But if you followed the steps of extreme weight manipulation, the real answer is that you weigh somewhere between 185 and 190 pounds. That’s 15-20 pounds more than the “cutoff” weight of 170.
24 hours before you stepped into the cage, however, you did in fact weigh 170 pounds. You had to. Friday night was the official weigh-in where you and your opponent both stripped down to your skivvies, stepped on the scale in front of the judge, and prayed that the number on the scale hit 170 or lower.
But once you stepped off that scale it was a race to gain weight.
I find this kind of physiological puppetry very interesting. Most of us regular guys have a hard time gaining or losing just 5 pounds at a time.
But the top combat athletes can lose up to 30 pounds in just 5 days leading up to the fight. Then they can gain nearly all of it back in the 24 hours between weighing in and going toe-to-toe.
They do this to gain a massive competitive advantage. In other words, the bigger guy who retains more of his strength, agility, and endurance will likely win.
The guy who weighs in at 170 — and then fights at 170 — often has a world of hurt coming his way.
That’s why Anderson Silva – arguably the world’s best MMA fighter — normally fights in the 185-pound class even though he actually weighs 215 pounds. A few days before he fights, Anderson “cuts” 30 pounds to make weight…then gains most of his weight back in 24 hours in time for his fight.
Georges St Pierre — arguably the world’s 2nd best fighter – normally walks around at 195 pounds. He ends up cutting 25 pounds to make his 170 pound weight class, and then gains 20 of it back before his fight.
Sneaky, huh?
Just how do these guys do it? And what does this rapid weight loss and weight gain do to their performance?
My Extreme Weight Manipulation Experiment
I’m lucky enough to be friends with Dr. John Berardi and Martin Rooney, two guys who regularly work with UFC athletes.
Recently, I told them I wanted to see what cutting weight was like. Is it really possible for a regular guy like me to drop 20 pounds in a few days then gain all of it back in 24 hours?
And if it was possible, what would it feel like? I heard cutting weight was one of the hardest things fighters do throughout their career. Was I man enough to handle it? Or would I give up when things got tough?
They agreed to help me cut 20 pounds in one week, and then put it all back on again in 24 hours.
Nervous doesn’t even begin to explain how I felt.
Low extreme weight manipulation can go horribly, horribly wrong. Even a lot of UFC guys don’t know how to do it the smart way. Instead, they put their bodies in real harm by doing stupid things like taking a lot of diuretics, not drinking any water, skipping meals, wearing trash bags while exercising (sometimes in the sauna) and generally being idiotic.
They lose weight, of course. But they also lose energy and power and develop one bad temper. None of which helps during fight time.
With the help of Dr. Berardi and Rooney, I decided to take a smarter route, instead of putting my health in serious jeopardy.
I started at 190.2 pounds and had 5 days to lose 20 pounds.
Here’s a breakdown of the nutritional strategies we used — the same one Georges St Pierre and other elite MMA fighters use before a big fight. (Remember: we know this because Dr. Berardi is Georges’ nutrition coach).
STRATEGICALLY DECREASE WATER CONSUMPTION
Dropping weight fast is all about manipulating your water and sodium levels.
For a fighter who wants to cut weight quickly and safely, here’s how much water he would consume in the 5 days leading up to his weigh-in:
Sunday – 2 gallons
Monday – 1 gallon
Tuesday – 1 gallon
Wednesday – .5 gallons
Thursday – .25 gallons
Friday – No water till after weigh-in at 5PM.
As you can see, the amount of water starts high with two gallons and decreases with each day till he’s drinking hardly any water on Thursday and Friday.
This is to ensure their body gets into “flushing mode.”
By drinking lots of water early on, the fighter’s body will down-regulate aldosterone, a hormone that acts to conserve sodium and secrete potassium.
And when he suddenly reduces the amount of water he drinks in the middle and end of the week, his body will still be in flushing mode, meaning he’ll hit the bathroom to pee a lot even though he’s hardly drinking any water.
What happens when you excrete more fluid than you take in? Bingo! Rapid weight loss.
DON’T EAT MORE THAN 50 GRAMS OF CARBS PER DAY
Since one gram of carbohydrate pulls 2.7 grams of water into the body, it’s important for fighters to keep their carb intake low.
By doing this, they also deplete muscle glycogen (a source of energy) and keep their body in “flush mode”.
DON’T EAT FRUIT, SUGAR, OR STARCHES
These are carbs that should be avoided entirely while cutting.
EAT MEALS THAT CONTAIN A LOT OF PROTEIN AND FAT
Fighters have to eat something. Since they’re avoiding carbs, Dr. Berardi advises them to load up on high-quality protein like meats, eggs or a vegetarian sources of protein. It’s also the perfect opportunity to eat lots of leafy vegetables (like spinach) and cruciferous vegetables (like broccoli and cauliflower).
Georges St Pierre normally has his meals prepared by a private chef so he doesn’t even have to think about this stuff or make decisions. Recommended reading: here’s an entire article detailing GSP’s training diet.
DON’T EAT SALT
Since the body likes to hold on to sodium (which will hold on to water), dropping salt helps the fighter’s body flush water out.
CONSIDER A NATURAL DIURETIC
This step isn’t always necessary, but it can help when you’re getting down to the wire and still need to lose water. Opt for a natural diuretic like dandelion root, but wait until the last 2 days to use it.
TAKE HOT BATHS
We sweat a lot in hot environments. However, we sweat the most in hot, humid environments. Since hot water offers both heat and 100% humidity, fighters lose water quickly by taking hot baths and fully submerging everything but their nose for 10 minutes at a time.
SIT IN THE SAUNA
This is the “finishing touch” to flush the last few pounds of water and is only used on the last few days leading up to the weigh-in.
The Weight Cut Schedule
So if we take all of that and break it into a weekly plan, it looks like this:
SUNDAY
Carbs: Less than 50 grams per day. No fruit, starches, or sugars.
Protein and Fat: As much as you want in 3 meals
Water: 2 gallons
Salt: None
MONDAY
Carbs: Less than 50 grams per day. No fruit, starches, or sugars.
Protein and Fat: As much as you want in 3 meals
Water: 1 gallon
Salt: None
TUESDAY
Carbs: Less than 50 grams per day. No fruit, starches, or sugars.
Protein and Fat: As much as you want in 3 meals
Water: 1 gallon
Salt: None
WEDNESDAY
Carbs: Less than 50 grams per day. No fruit, starches, or sugars.
Protein and Fat: As much as you want in 3 meals
Water: 0.5 gallon
Salt: None
Sauna in afternoon
THURSDAY
Carbs: Less than 50 grams per day. No fruit, starches, or sugars.
Protein and Fat: As much as you want in 3 meals
Water: 0.25 gallon
Salt: None
Sauna in afternoon for 30 minutes, hot water bath at night
FRIDAY (WEIGH IN AT 6PM)
Carbs: Less than 50 grams per day. No fruit, starches, or sugars.
Protein and Fat: Eat 2 very small meals until weigh in
Water: None till weigh-in
Salt: None
Sauna until weight is met
So that all looks fine on paper. But what does it actually feel like to go through it?
One word: Hell.
I started my cut on Sunday at 190 pounds. Here’s a quick rundown of what it looked like.
SUNDAY – 190 POUNDS
I carry a gallon water jug with me wherever I go, which makes me feel ridiculous. But I have to make sure I get my two gallons of water in. Overall, though, I feel fine. It actually doesn’t seem that difficult. I’m not sure what the big deal is.
MONDAY – 187 POUNDS
I’m starting to miss the taste of salt. All of my food is bland. Now I’m drinking one gallon of water instead of two. Still not that bad.
TUESDAY – 182 POUNDS
I go to the bathroom 13 times in one day. A new record, I believe. And I’m still drinking a gallon of water.
WEDNESDAY – 179 POUNDS
Now I’m down to half gallon of water per day, which means I have to ration it out, which feels weird. I have a little with breakfast, a little with lunch, and a little with dinner. It’s definitely not enough water.
My mouth is dry. I feel dehydrated. I’m drinking straight espresso instead of drip coffee because it contains too much water.
In the evening, I try my first hot water bath. I generally enjoy baths, but this one’s different. My apartment’s water doesn’t get as hot as Dr. Berardi wants it to be — “hot enough to cause moderate pain but not burn your hand” — so I fill two pots and a kettle with water, put them on the stovetop until they boil, and pour them into the bath tub.
I get into the bath and immediately regret the decision.
10 minutes later, I’m lying naked in the middle of my living room trying to catch my breath. My eyes are rolled back into my head. My entire body feels like a giant heartbeat. I want to drink some water, but can’t.
This is starting to be less fun.
THURSDAY – 175 POUNDS
I am a zombie. A zombie who sits. Mostly in the sauna or on the couch.
In the sauna I watch beads of sweat collect on my skin. I see my precious water run down my arms and chest and legs and know that I won’t be able to replenish any of it when I get out.
I only have .25 gallons of water to last me the entire day. I’m ready for this to be over.
FRIDAY – 169.7 POUNDS AT 5PM
I look sick, very sick.
I spend the last 30 minutes before the weigh-in in the sauna and drink four sips of water throughout the entire day…
What Cutting Weight Does To Performance
OK, I’ll save you the rest of the journal entries and share some performance data.
While the fighters are tested in competition, no one has ever really documented how much strength or power they lose by dehydrating. (Or how much strength and power they regain after they get all their weight back.)
So we decided to check.
And it turns out, losing 20 pounds in 5 days is not conducive to being strong, powerful, or agile. (Surprise!) I couldn’t jump as high, lift as much weight, or run as fast or as long as I had just a week before during our baseline testing.
POWER TEST: VERTICAL JUMP
Baseline: 31.7 inches
After Dehydration: 27.6 inches
STRENGTH ENDURANCE TEST: 225-POUND BENCH PRESS
Baseline: 15 reps
After Dehydration: 5 reps
ENDURANCE TEST: MAX TIME ON TREADMILL
Baseline: 3 minutes and 14 seconds of sprinting at 8mph with 6% incline
After Dehydration: 1 minute and 28 seconds of sprinting at 8mph with 3% incline
It’s no wonder these guys try to gain all their weight back immediately after weighing in. They’d be screwed if they didn’t.
Speaking of which…
The Smart Way To Gain Weight Fast
Once UFC athletes cut weight and weigh-in, they’d never be able to perform at a top level. (Which is obvious from my less-than-stellar performance in the gym).
So what do they do next? They gain as much weight as humanly possible in 24 hours.
Here’s how they do it. (And how I did it, too.)
DRAMATICALLY INCREASE WATER INTAKE.
According to Dr. Berardi, the body can absorb only about 1 liter (2.2 pounds) of fluid – at maximum – in an hour. So he advises the fighters he works with to not to drink any more than that. Instead, he tells them to sip 1 liter (2.2 pounds) of water per hour.
However, the fighters won’t retain all that fluid. In fact, probably about 25% of it will be lost as urine.
So, here’s the math for someone like Georges St Pierre:
9 liters (20 pounds) of water to get back.
11 liters (25 pounds) of fluid between Friday weigh-in and Saturday weigh-in to get it all back.
24 hours in which to do it. 8 of which he’ll be sleeping and 3 of which will be leading up to Saturday weigh-in.
This leaves 13 total hours for rehydration.
So as soon as Georges steps off the scale, he literally slams a liter of water and carries the bottle around with him, refilling it and draining it every hour until 3 hours before his fight. (There isn’t a bathroom in the cage.)
EAT AS MUCH CARBOHYDRATE (AND PROTEIN AND FAT) AS YOU WANT
Now’s also the time for fighters to load up on carbs and pull all the water they’re drinking back into their muscles. It also helps them feel more human and look less sickly. (Something I definitely experienced during my super-hydration phase.)
Dr. Berardi has his fighters eat a big meal directly after they weigh in. He doesn’t restrict calories – his athletes can eat as much as they want in that meal as long as it’s healthy food like lean meats, sweet potatoes, rice, and vegetables. (Gorging on junk food is a bad idea.)
Then on Saturday (fight day), Dr. Berardi has his fighters eat a satisfying amount of healthy food in a few small meals leading up to the fight.
ADD SALT TO EVERYTHING
Since sodium helps the body retain water, fighters are encouraged to add extra salt to their meals.
Here’s what my super rehydration schedule looked like:
The Weight-Gain Schedule
FRIDAY AFTER WEIGH-IN
Carbs: Eat as much as you want in one meal after weigh-in and testing
Protein and Fat: Eat as much as you want in one meal after weigh-in and testing
Rehydration Beverage: Drink 1 liter of water mixed with 1/2 scoop of carbohydrate/protein drink for every hour you’re awake. (We used Surge Workout Fuel.)
Salt: Salt food
SATURDAY
Carbs: Eat satisfying amount in four meals before weigh-in
Protein: Eat satisfying amount in four meals before weigh-in
Rehydration Beverage: Drink 1 liter of water mixed with 1/2 scoop of carbohydrate/protein drink for every hour you’re awake but stop 3 hours before testing.
What Gaining Weight Does To Performance
First things first: Personally, I ended up gaining 16.9 pounds back in 24 hours. Not bad.
But the real question: How much strength and power do you really gain when you super-hydrate?
Answer: A lot.
While I didn’t perform as well as my baseline (when I did all the performance tests before I started the experiment), I got really close. Which means that even though I put my body through a week of torture, it was almost 100%.
And I totally annihilated my performance numbers from just 24 hours before when I was sickly and dehydrated.
I ran faster and longer, jumped higher, and lifted more weight for more reps.
POWER TEST: VERTICAL JUMP
Baseline: 31.7 inches
After Dehydration: 27.6 inches
Re-hydrated: 29 inches
STRENGTH ENDURANCE TEST: 225-POUND BENCH PRESS
Baseline: 15 reps
After Dehydration: 5 reps
Rehydrated: 12 reps
ENDURANCE TEXT: MAX TIME ON TREADMILL
Baseline: 3 minutes and 14 seconds of sprinting at 8mph with 6% incline
After Dehydration: 1 minute and 28 seconds of sprinting at 8mph with 3% incline
Rehydrated: 3 minutes and 25 seconds of sprinting at 8mph with 6% incline
Lose Weight. Gain Weight. Fight.
For an MMA fighter, this is about the time when he’d be getting ready to step in the cage and fight, which means it’s about the same time you’d turn on the TV and see him in his corner, jumping up and down, getting psyched and ready for battle.
How much does he weigh?
It’s safe to say at least 10-30 pounds more than the weight class he’s fighting in.
And now you know the “secret” to extreme weight manipulation, something 99.9% of guys who watch MMA will never know.
Pretty cool, right?
The Highest Bar. Life Elevated. PureClean Performance