What Is Weight Cutting? Meaning, Methods and Risks

Contents

Weight cutting means losing weight quickly in the days before a weigh-in so you can compete in a lower weight class, then regaining it before the fight. Most of the weight you “cut” is water and stored carbohydrate, not fat. The goal is to step on the scale at the limit and step into the ring or cage heavier, and ideally bigger, than your opponent.

What does “weight cut” mean?

A weight cut is the short-term drop in body weight a fighter makes to hit a weight-class limit. It is followed by rapid regain after the weigh-in. It is not the same as dieting, although the two are usually combined.

The ACSM consensus statement on weight-category sports separates the two parts (Burke et al., 2021):

	Chronic weight loss	Acute weight loss (“making weight”)
What is lost	Body fat (and some muscle if it goes too fast)	Mostly water, glycogen and gut content
Timeframe	Weeks to months, during fight camp	Hours to days before the weigh-in
Comes back after weigh-in?	No, if done properly	Yes, and it’s meant to
Typical tools	Calorie deficit, training	Low-carb/low-fibre diet, sodium and fluid manipulation, sweating

When fighters say “cutting weight”, they usually mean the acute part. In practice, a good cut is mostly chronic with a small acute finish.

Why do fighters cut weight?

Fighters cut weight to compete against opponents who are lighter than them on fight night. If you weigh in at 70 kg and rehydrate to 76 kg, you are fighting at a size the weight class wasn’t designed for.

The ACSM statement calls this a “theoretical advantage” (Burke et al., 2021), but data suggest it can be real. In a study of 708 MMA fighters and 1,392 male boxers, winners regained more weight after the weigh-in than losers. In MMA, winners gained back 8.7% of body mass against 7.9% for losers. Each extra percentage point regained raised the odds of winning by 7% in MMA and 13% in boxing (Baribeau et al., 2023). The authors say these findings raise fair-play and safety concerns.

That incentive is why the practice is so widespread. In a survey of combat athletes summarised by the ISSN, 87% restricted food, 83% used water loading, 79% restricted fluids, 51% used a sauna and 43% trained in sweat suits or plastics (ISSN, 2025).

What does a weight cut look like?

A typical weight cut runs from a long, slow fat-loss phase into a short, sharp water phase, then a refill. Here is the general shape, not a plan to copy:

Phase	Typical duration	What happens
Fight camp	8–10 weeks	Gradual loss, commonly 0.5–1 kg a week (ISSN, 2025)
Fight week	Last ~5–7 days	Carbs and fibre reduced; each can lower body mass by about 1–2% (ISSN, 2025)
Final 24–48 h	1–2 days	Sodium and fluid reduced; sometimes a supervised sweat session
After weigh-in	Hours to ~1.5 days	Fluids, electrolytes and carbohydrate to regain as much as possible

Real-world cuts are often far more extreme. Seven UK MMA athletes lost an average of 8% of body mass in the week before competition. All of them were dehydrated at the official weigh-in, and 43% were severely dehydrated. They then regained 11.7% in the ~32 hours before the fight (Matthews & Nicholas, 2017).

If you are planning your first cut, the step-by-step version is in weight cutting for beginners. For how much is realistic at different stages, see how much weight you can cut.

Which methods are safe, and which are dangerous?

Methods that change what you eat and drink over several days are relatively safe when planned. Methods that force out water in a few hours through heat, drugs or vomiting are the ones linked to collapse and death.

Method	Verdict
Gradual calorie deficit during camp	Recommended: the foundation of any cut
Low-carb, low-fibre diet in fight week	Acceptable when planned: empties glycogen water and gut content
Water loading plus sodium reduction	Acceptable when planned: the ISSN notes both increase urine output (ISSN, 2025)
Sauna or hot bath	Small amounts only, supervised: the ISSN puts the optimal amount at roughly 2–4% of body mass within 24 h of weigh-in (ISSN, 2025)
Exercising in rubber or plastic suits, in the heat, while restricting fluid	Avoid: the method used in the 1997 wrestling deaths (CDC, 1998)
Diuretics, laxatives, enemas, diet pills, vomiting	Never: the ISSN calls these potentially harmful and does not endorse them (ISSN, 2025)

How weigh-in timing makes weight cutting possible

The more time there is between the weigh-in and the fight, the more weight a fighter can cut and regain. That makes weigh-in timing a major driver of how extreme cuts become.

The ISSN groups combat sports by weigh-in window (ISSN, 2025):

Time from weigh-in to competition	Examples in the ISSN table	Suggested net sweat loss (from a hydrated start)
Under 4 hours	NCAA and Olympic freestyle wrestling, BJJ, ADCC	0–3%
4–12 hours	Amateur boxing, amateur Muay Thai	2–4%
12–24 hours	Judo, Olympic boxing, taekwondo	3–5%
24–36 hours	Professional MMA, boxing, kickboxing and Muay Thai	4–6%

Weigh-in times differ between events, so check your own rulebook. Day-before weigh-ins, as in the UFC, are what make big cuts possible. See the UFC weight cut for how that works at the top level. Same-day weigh-ins leave almost no time to recover, which is why a large cut before one is dangerous.

The rehydration phase

Rehydration is the second half of every weight cut. The fighter drinks fluids with electrolytes and eats carbohydrate to refill water and glycogen before the fight. It is what the whole cut is built around, and it is never complete if the cut was too big.

The UK MMA fighters in the Matthews study regained more than they had lost (Matthews & Nicholas, 2017). But even a small change of 2.5% in body weight from dehydration can impair performance (ISSN, 2025). A fighter who can’t fully rehydrate in time walks into the fight weaker, not stronger. How to do it properly: rehydrating after the weigh-in.

Risks and documented deaths

The risks of weight cutting range from worse performance to heat illness and death. The most dangerous combination is intense exercise in the heat while already dehydrated.

• 1997, US college wrestling: three previously healthy wrestlers, aged 19–22, died within about five weeks of each other. Each was trying to lose the last 4–15 lb in the hours before a weigh-in by restricting food and fluid and exercising hard in vapor-impermeable suits in hot environments (CDC, 1998).
• 2015, MMA: Yang Jian Bing died in December 2015, reportedly from weight-cutting complications, before a scheduled ONE Championship bout (IMMAF, 2015).

The Matthews study concluded that the size of the cuts and the methods used by the UK MMA fighters were “comparable to those which have previously resulted in fatalities” (Matthews & Nicholas, 2017). The long-term health effects of repeated cuts are still unknown (ISSN, 2025).

What is a hydration test, and what other reforms exist?

A hydration test measures how concentrated your urine is (urine specific gravity). Dehydrated athletes produce concentrated urine and fail, even if they are on weight. It is one of several reforms sports bodies have introduced to make extreme cuts impractical.

• NCAA wrestling (after 1997): banned vapor-impermeable suits, saunas, steam rooms, laxatives, diuretics and self-induced vomiting. It also required urine specific gravity below 1.020 when a wrestler’s minimum weight is set, capped planned loss at 1.5% of body weight per week, and moved weigh-ins closer to competition (Gibbs et al., 2009). More in the wrestling weight cut guide.
• ONE Championship (announced December 2015): replaced the traditional cut with a “walking weight” system. Weight is tracked regularly, with multiple weigh-ins and tests before and during fight week (IMMAF, 2015).
• Association of Boxing Commissions (2017): approved four extra MMA weight classes at 165, 175, 195 and 225 lb (74.8, 79.4, 88.5 and 102.1 kg). A 10-point medical plan listed earlier weigh-ins, day-of-event weight checks, dehydration testing and 30- and 10-day pre-fight weight checks (ABC, 2017).

The ACSM statement backs the same direction: minimum competition weights based on preseason body composition, a shorter gap between weigh-in and competition, and bans on unhealthy weight-loss techniques (Burke et al., 2021).

The evidence-based alternative

The evidence-based alternative is to make most of your weight loss chronic and planned, and keep the acute cut small and matched to your weigh-in window. Better still, work with a sports nutrition professional (Burke et al., 2021).

In practice, that means:

1. Choose a realistic weight class. The ISSN suggests staying around 12–15% above your division limit outside of camp (ISSN, 2025). If you’re far above that, go up a class. See combat sports weight classes.
2. Lose fat gradually through camp at 0.5–1 kg a week, eating enough to train well.
3. Use diet-based fight-week tools first (carbs, fibre, sodium, fluids) and keep sweating to a small, supervised finish, if you use it at all.
4. Plan rehydration before you plan the cut.

MyFightPrep tracks your weight trend toward the fight, flags when you’re behind schedule and plans water and salt for fight week, so the cut stays small. Free.

Important

This guide is general information, not medical advice. Weight cutting through dehydration can be dangerous and, in the worst cases, fatal. Talk to your coach and a doctor or sports dietitian before your first cut. Athletes under 18, including high school wrestlers, should not dehydrate to make weight at all. Stop immediately and get help if you feel dizzy, confused, have palpitations or cramps, or stop sweating while hot.

Frequently asked questions

What does a weight cut look like?

It usually starts with 8–10 weeks of gradual dieting in fight camp, followed by a final week of lower carbs, lower fibre, sodium and fluid changes, and sometimes a short sweat session before the weigh-in. After stepping off the scale, the fighter rehydrates and refuels before the fight.

Is weight cutting worth it?

It can give a size advantage: in a study of 2,100 professional fighters, those who regained more weight after the weigh-in were more likely to win. But dehydration of about 2.5% of body weight can already impair performance, and large cuts carry real health risks, so small, planned cuts are the only sensible version.

How long should I weigh cut?

The gradual part should cover your whole fight camp, typically 8–10 weeks, at about 0.5–1 kg per week. The acute water-based part belongs in the last few days before the weigh-in, and how much you can safely take off depends on how long you have to rehydrate.

What is a hydration test in MMA?

A urine test that checks how concentrated your urine is (urine specific gravity). If you are dehydrated, your urine is too concentrated and you fail, even if you are on weight. ONE Championship and NCAA wrestling use hydration testing to stop athletes from dehydrating to make weight.

Is it good to cut weight?

Losing body fat gradually to reach a sensible weight class is fine for healthy adults. Dehydrating yourself to make weight is not good for your health, and young athletes, beginners and anyone with same-day weigh-ins should avoid it.

Sources

This guide is based on the works below. Numbers in the text refer to them.

1. Burke LM, Slater GJ, Matthews JJ, Langan-Evans C, Horswill CA (2021). ACSM Expert Consensus Statement on Weight Loss in Weight-Category Sports
2. Ricci AA, Evans C, Stull C, et al. (2025). International society of sports nutrition position stand: nutrition and weight cut strategies for mixed martial arts and other combat sports
3. Matthews JJ, Nicholas C (2017). Extreme Rapid Weight Loss and Rapid Weight Gain Observed in UK Mixed Martial Arts Athletes Preparing for Competition
4. Baribeau V, Kirk C, Le DQ, et al. (2023). Rapid Weight Gain and Weight Differential Predict Competitive Success in 2100 Professional Combat-Sport Athletes
5. Centers for Disease Control and Prevention (MMWR) (1998). Hyperthermia and Dehydration-Related Deaths Associated with Intentional Rapid Weight Loss in Three Collegiate Wrestlers — North Carolina, Wisconsin, and Michigan, November–December 1997
6. Gibbs AE, Pickerman J, Sekiya JK (2009). Weight Management in Amateur Wrestling
7. Association of Boxing Commissions and Combative Sports (ABC) (2017). Minutes of the 29th Annual Association of Boxing Commissions Conference
8. International Mixed Martial Arts Federation (IMMAF) (2015). One Championship Bans Weight Cutting By Dehydration