Ethics CasesSport

Cases · ONE Championship / State athletic commissions · 2013–present

Weight Cutting in Combat Sports and the Death of Yang Jian Bing

In mixed martial arts and other combat sports, fighters often lose large amounts of weight through dehydration before weigh-ins, then regain it before fighting. The goal is to compete against smaller opponents. In December 2015, 21-year-old Chinese fighter Yang Jian Bing died in Manila after a failed weight cut before a ONE Championship event; an autopsy attributed his death to a heart attack. ONE responded by banning weight cutting through dehydration, introducing hydration tests and weight tracking. In 2013, Brazilian fighter Leandro Souza had died of a stroke while cutting weight for a Shooto event. In 2017, the California State Athletic Commission adopted a package of weight-cutting rules. Most promotions still rely on day-before weigh-ins. The case raises questions about collective-action problems, athlete autonomy and regulators' duty of care.

By Tanner Simkins, editor

Timeline

  1. Brazilian fighter Leandro Souza dies of a stroke while cutting weight for Shooto Brazil.
  2. Yang Jian Bing dies in Manila after a failed weight cut before a ONE Championship event.
  3. ONE bans weight cutting by dehydration and announces hydration testing and weight tracking.
  4. The California State Athletic Commission adopts a package of weight-cutting rules.

The ethical issues

  • Collective action: if everyone cuts, no one gains, but anyone who stops is at a disadvantage.
  • Athlete autonomy vs. protection: whether fighters can accept the risks of dehydration.
  • Regulatory design: weigh-in timing, hydration testing and weight classes.
  • Competitive fairness: rehydrated fighters facing much lighter opponents.
  • Responsibility of promoters, commissions and coaches.

Stakeholders

StakeholderInterests & obligations
FightersHealth, competitiveness and careers.
PromotersEvent reliability and liability.
Athletic commissionsFighter safety and enforcement.
Coaches and nutritionistsTheir methods and fighters' health.
OpponentsFair matchups.
FansFighter welfare and the quality of bouts.

The case

Combat sports divide competitors into weight classes so that fighters face opponents of similar size. In practice, many fighters “cut” weight. They lose large amounts, mostly water, in the days before the official weigh-in through restricted fluids, saunas, sweat suits and sometimes diuretics. They then rehydrate before the fight, often 24 hours or more later, and compete well above the class limit.[1] The aim is to face a smaller opponent. Because most fighters do it, a fighter who refuses may be at a disadvantage.[1]

Severe dehydration strains the heart and kidneys, can impair heat regulation, and may make the brain more vulnerable to injury.[1]

Background

Yang turned professional in 2013. He fought his first four bouts for another promotion before debuting for ONE in May 2015, and suffered his first loss that June, on a card on which he fought twice in the same night.[2] He was scheduled to face Filipino fighter Geje Eustaquio in a three-round flyweight bout at ONE: Spirit of Champions in Manila. Neither fighter attended the official weigh-in the day before the event, and ONE initially said little about Yang’s condition. Eustaquio wrote on Facebook that his opponent had been rushed to hospital with dehydration and possible heat stroke.[2] ONE later released the autopsy report, which contradicted circulating reports about the cause of death. Yang’s remains were repatriated to China after a private vigil.[2]

Yang’s death was not the last. Wikipedia records the deaths of Muay Thai fighters cutting weight in Thailand in 2016 and in Australia in 2017. An acute care physician in Western Australia warned regulators that without rules to stop extreme weight cutting, more deaths were “inevitable,” and called for hydration tests to decide who could compete.[1]

The rules and governance

ONE’s December 2015 program set detailed rules.[3] Fighters log their walking weight and daily training weight online and are assigned a weight class based on those data and random checks. They cannot drop a class within eight weeks of an event. During fight week, weight is checked daily, and urine specific gravity, a hydration measure, is tested the day after arrival and three hours before the event. A fighter outside the limit, or who fails a hydration test, is disqualified. IV rehydration is banned. Catchweight bouts are allowed only if the heavier fighter weighs no more than 105% of the lighter one. The rules also cap how far over the class limit a fighter may be in the weeks before an event, falling to zero three weeks out.[3] ONE’s CEO invited the UFC and Bellator to follow its lead.[3]

California’s 10-point plan, passed unanimously in May 2017, took a different approach.[7] It increased fines for missing weight, added a fight-day weight check, created new weight classes at 165, 175, 195 and 225 pounds, and allowed weight checks 30 and 10 days before a fight. It also licensed fighters by weight class, giving doctors more say over the lowest weight a fighter can safely make. The UFC, Bellator and Invicta wrote letters supporting the plan, but promotions are not obliged to adopt the new weight classes.[7] The commission’s December 2015 summit had already produced the early weigh-in, which is now widely used in North American MMA.[7] Some commissions also punish dangerous cuts. In one case, a regulator suspended a Bellator fighter for six months and fined him $2,500 after he posted a video of himself vomiting while cutting weight.[1]

Deaths

In September 2013, Brazilian fighter Leandro Souza died of a stroke while cutting weight for a Shooto Brazil event. He reportedly used diuretics and had to lose a large amount of weight in a week. The event was canceled.[5][6]

In December 2015, Yang Jian Bing, a 21-year-old Chinese flyweight, was preparing for a ONE Championship event in Manila. He was hospitalized after a failed weight cut and died on December 11. The official autopsy attributed his death to a heart attack.[2]

ONE’s response

Within two weeks, ONE Championship, then based in Singapore, banned weight cutting by dehydration. Under its new system, fighters’ weights are tracked during training, and they must compete close to their “walking weight.” During fight week, they face daily weigh-ins and urine tests for hydration. Fighters who fail either test can be disqualified.[3][4] The promotion called the program “the first of its kind for combat sports.” Its CEO, Victor Cui, said: “By banning weight cutting by dehydration, we are leading the way globally for enhanced safety standards.” He invited “the other two major global MMA organizations, Bellator and UFC, to follow in our footsteps.”[4] Doctors could also order more tests at their discretion.[4]

Regulators

In the United States, athletic commissions regulate combat sports state by state. In May 2017, the California State Athletic Commission adopted a package of weight-cutting rules, including earlier weigh-ins, dehydration checks and fight-day weight checks. Fighters who regain more than 10 percent of their weight may be advised to move up a weight class.[7] A fighter who misses weight forfeits 20 percent of any win bonus to the opponent, on top of the existing 20 percent fine on show money, and repeat offenders are advised to move up.[7] The commission’s executive officer, Andy Foster, who wrote the plan, said: “I can say unequivocally that the promoters see this as a problem also… this is a problem for the entire industry.” He gave an example of why the 30-day check mattered: “If we have a fighter contracted for 155 and they’re 195 pounds 30 days out, maybe it’s time to get with the promoter, get with the medical committee.” He also worried that fighters might cut weight for the early checks as well as for the weigh-in.[7] The Association of Boxing Commissions said it would recommend the plan to all its members.[7] Most major promotions continue to hold weigh-ins the day before fights.[1]

Aftermath

California’s fight-day weight checks produced data that researchers used to test the main reason fighters cut weight. A 2020 study analyzed 124 fighters, the winners and losers of bouts at five events sanctioned by the commission. It found that neither fight-night body mass nor the amount regained between weigh-ins predicted who won. Fighters typically competed at a body mass “at least 1-2 divisions higher” than the class they had weighed in for.[8] The authors suggested the findings “may provide impetus for governing bodies and coaches” to act against extreme weight loss and regain.[8] If that finding holds, the cut carries its health risks without delivering the edge that motivates it. But it is hard for one fighter to stop alone while opponents keep cutting.[1][8]

The core dilemma

Fighters cut weight because their opponents do. Each fighter faces pressure to take the same risks, and no one can stop alone without losing ground. Should promoters and regulators override fighters’ choices to protect them from one another, and if so, how?

Competing values

  • Autonomy vs. protection: adults’ freedom to take risks against preventing serious harm.
  • Competition vs. health: seeking an edge against bodily safety.
  • Tradition vs. reform: established practice against new systems.
  • Uniformity vs. local control: consistent rules against state-by-state regulation.

Strongest arguments

For strict rules: cutting weight is dangerous and provides no net advantage when everyone does it. Only binding rules can end the cycle, and regulators have a duty to protect fighters.

For a lighter touch: hydration testing is costly and imperfect, and fighters, coaches and nutritionists can manage cuts more safely than in the past. Overly strict systems may push weight loss into earlier, less visible methods.

Applying the frameworks

Ethics of care

The care lens focuses on the fighter’s body and wellbeing, and on the responsibility of promoters, coaches and commissions who see dangerous weight cuts happen and know the culture rewards them.

Utilitarian

A utilitarian lens weighs the competitive and commercial costs of stricter weigh-in systems against the harm of deaths and serious injuries. It asks which rules, such as hydration testing, weight tracking or fight-day checks, best reduce harm overall.

Rights

A rights lens weighs a fighter’s autonomy to choose risky practices against the risk that, when everyone cuts weight, choosing not to is not a real option. Is regulation justified paternalism or a protection of fair competition?

Walk it through: the Simple Decision Model

  1. Spot the issue. You are a promotion executive after a young fighter dies while cutting weight before your event. The stakeholders include fighters, their teams, opponents, medical staff, regulators, fans and broadcasters. The codes in play are your own rules and the local athletic commission’s regulations.
  2. Gather facts. What happened in the days before the weigh-in? What do doctors say about dehydration and rehydration? What systems exist elsewhere?
  3. Test options. Options: (a) keep current weigh-ins and add medical checks; (b) move weigh-ins earlier and add fight-day weight checks; (c) ban dehydration cutting and use weight tracking and hydration tests. Weigh safety, practicality, fighter autonomy and competitive fairness.
  4. Check codes and law. Would the rules protect fighters who feel pressure to cut? Could you defend your approach after another death?
  5. Decide and document. Record the medical advice, the rule changes and how they will be enforced.
  6. Communicate and follow up. Communicate the new rules clearly to fighters and managers, educate camps, and publish data on hydration failures and missed weights.

What’s settled and what’s contested

  • Settled: the deaths of Souza and Yang; ONE’s ban and hydration testing; California’s rule package.
  • Contested: how effective hydration testing is; the best weigh-in timing; whether other promotions should follow ONE.

Why this case matters

Weight cutting is a clear example of a collective-action problem in sport. It shows how rules can protect athletes from pressures that each one faces alone.

Key terms

Duty of care
The responsibility of coaches, organizations and institutions to protect the health, safety and well-being of those in their charge. It is not a license for total control.
Paternalism (hard and soft)
Restricting someone’s choices for their own good. Hard paternalism overrides competent, informed adults; soft paternalism steps in when information or autonomy is compromised.
Non-maleficence
The duty to avoid causing harm, often paired with care ethics when setting safety rules.
Controls
Concrete safeguards that make ethics operational: training, disclosure forms, testing, monitoring, hotlines. Ethics needs principles, process and controls.

Definitions from the Ethics Cases glossary.

Discussion questions

  1. Weight cutting is a classic collective-action problem. Why do fighters keep doing it even though it is dangerous?
  2. Should adults be allowed to take health risks to gain a competitive edge? Where should the line be?
  3. ONE adopted hydration testing, while most promotions did not. What are the costs and benefits of each approach?
  4. Who bears responsibility when a fighter dies cutting weight: the fighter, coaches, the promoter or regulators?
  5. How could weigh-in rules be designed to make dangerous cuts pointless?

Sources

  1. Weight cutting — Wikipedia
  2. ONE FC's Chinese MMA fighter dies of heart attack – Autopsy report — Rappler
  3. ONE Championship announces new weigh-in program following fighter's death — MMA Fighting
  4. ONE Championship overhauls weigh-ins, fighters to compete at 'walking weight' — MMA Junkie
  5. Leandro 'Feijao' Silva dies from stroke before Shooto 43 weigh-ins — MMA Fighting
  6. Leandro Souza reportedly took diuretic pills before Shooto weigh-ins — MMA Fighting
  7. CSAC passes ground-breaking package of weight-cutting regulations — MMA Fighting
  8. Worth the Weight? Post Weigh-In Rapid Weight Gain is Not Related to Winning or Losing in Professional Mixed Martial Arts (Int J Sport Nutr Exerc Metab, 2020) — PubMed