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ONE Championship Weight Cutting - How Does It Work?

Robert Green
Published: July 8, 2023
Updated: July 8, 2023

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ONE Championship, Asia's largest global sports media property, stands out in the constellation of combat sports organizations for its unique approach to weight classes.

Unlike other organizations where weight cutting through dehydration is a common practice, ONE Championship has zealously adopted a different path. It's a path that emphasizes athlete wellness while simultaneously shaking up traditional weight class norms.

Itsuki Hirata after making weight in One FC.

In this post, we'll take a close look into the unique ONE Championship Weight Cutting rules. The cornerstone of these rules is the highly venerated Hydration & Weigh-In System. This system, revolutionary for combat sports, eschews weight-cutting via dehydration.

Instead, it creates a framework that ensures athletes remain hydrated, promoting optimal health and performance ahead of their bouts. But how does it differ from other organizations, and exactly how does it work? We'll explore this in depth.

From hydration tests to weigh-ins, let's dive into an unparalleled system that sets ONE Championship apart.


Don't want to read? Here's the main rundown of ONE’s Hydration & Weigh-In System:

  • ONE Championship's hydration and weigh-in system focuses on an athlete's "walking weight" to determine their natural weight without dehydration.
  • Athletes undergo hydration tests throughout the event week to ensure optimal hydration levels.
  • Athletes must pass the hydration test (1.025 or below urine specific gravity) to proceed to the weigh-in.
  • Weigh-ins require athletes to meet the prescribed weight limits of their contracted weight class.
  • Failure to pass the hydration test or meet the weight limits results in retests or disqualification, respectively.

Read on to learn even more about how One Championship does Weigh Ins.

A Detailed Explanation of ONE’s Hydration & Weigh-In System

If you've ever wondered about the mechanics of ONE Championship's hydration and weigh-in system, let me unravel the magic behind the screen. This innovative system, in essence, revolves around the concept of the athlete’s "walking weight".

But what does this mean, you ask?

In this image, Marlon Moraes is at a natural weight, during the weigh in for Moraes Lynch III.
In this image, Marlon Moraes is at a natural weight, during the weigh in. Source.

"Walking weight" refers to the natural weight at which the athlete trains under regular conditions, without undergoing the rigorous process of dehydration to drop pounds. This “walking weight” is tracked regularly under the contract period of an athlete with ONE Championship.

How does this system play out in real-time?

Let's begin with the time an athlete checks in at the hotel at the start of the event week. Their weight is evaluated promptly to ensure it falls within the prescribed limits of the contracted weight class. This is a crucial first step, setting the stage for the trials of weight and hydration to come.

Throughout the event week, athletes are compelled to take part in combined weigh-ins and hydration tests. The medical team tests athletes' hydration level via urine specific gravity tests. Each athlete presents a urine sample which is analyzed to ensure optimal hydration levels.

Only when an athlete passes the hydration test, achieving a urine specific gravity value of 1.025 or below, can they proceed to the weigh-in.

A urine hydration test, used by ONE Championship.
A urine hydration test, used by ONE Championship. Source.

Weigh-ins follow closely behind and demand the athlete to fall within the prescribed weight limits. Now, one might pause to wonder what happens if an athlete faces a hiccup at these crucial junctures. A missed mark at weigh-in or hydration test immediately demands a retest on the event day.

They must make the requisite weight and pass the hydration test in the second round to be eligible to compete.

However, any failure to pass the hydration test on event day directly results in disqualification from participating in the event. There is a small window of respite if an athlete passes the hydration test but overshoots the weight limitations.

If the athlete weighs within 5 percent of the opponent’s official weight and the opponent agrees, the bout can proceed as a catchweight event. But this leniency comes with a price. A certain percentage of the athlete's purse is given to the opponent due to the inability to make the contracted weight.

The endeavor for proper hydration and optimal weight does not cease following the bout. The athlete's post-bout weight should not exceed 5 percent over the weight class or catchweight limit.

OneFC official weight miss document, POST-BOUT WEIGHT CHECK Marat Grigorian
An official OneFC document. In this instance, the athlete did NOT fall within 105% of the upper limit. Source.

What ensues if this rule is flouted? Three strikes and you're out - the violation warrants an official warning, followed by a penalization of 25 and then 50 percent of the total fight purse, and a direct kiss goodbye to competing in the same weight class.

ONE Championship's Hydration & Weigh-In System shines a beacon of athlete welfare in the world of combat sports. The system’s attention to detail, from start to finish, ensures athletes are healthy and maintain a fighting spirit, as they step into the ovular ring, ready to inspire the world.

killerbeemma. Weigh-in pic comparisons.2018 vs 2020.

It’s a nuanced but potent shift that is driving combat sport away from the dangerous pitfalls of intense dehydration, championing instead an approach of optimal health and fitness while maintaining competitive integrity.

Controversy and Concerns

Despite the laudable intentions of ONE Championship’s Hydration & Weigh-In System, it has not been entirely exempt from the whisperings of controversy and concerns.

Sadly, a significant incident primarily contributed to the birth of this new system.

In 2015, the tragic demise of Chinese fighter Yang Jian Bing, allegedly from complications of a severe weight cut, spotlighted the dire need for a reformed weight-management system.

While the quick adaptation of the innovative weigh-in protocol initially appeared as a reactive push for positive PR in the aftermath of this event, its effectiveness and reliability are still under scrutiny today.

Critics of the new system include professionals such as Dr. Oliver Barley, a reputed expert in exercise physiology and sports science. Dr. Barley criticizes the system for its lack of scientific backing, pointing out the potential inaccuracies in hydration testing and the apparently arbitrary hydration cut-off limit of 1.025.

He questions the applicability of these hydration tests in detecting dehydration in combat athletes, underscoring the need for more rigorous scientific research.

Further concerns arise around the purported ease of manipulating these hydration tests. According to Dr. Barley, tricking the test is “ridiculously easy” and requires just a specific consumption of distilled water.

The doc openly admits to aiding athletes in "tricking" the test, leading one to question the robustness of a system where its checks can be so easily overridden.

Additionally, ONE’s rule of limiting weight gain to 5% on fight day presents potential health issues. This rule could potentially hinder proper recovery, as athletes eager to stay within the limits might withhold full rehydration and operate sub-optimally during their bouts.

Criticism isn't confined solely to medical professionals, as some fighters have also voiced their dissatisfaction with the processes. Reports of athletes dropping multiple divisions and confessing to cutting weight again, as well as advice from ONE officials on repeated cutting and hydrating throughout the day, bring the efficacy of the new system under question.

Nevertheless, the Hydration & Weigh-In system has carved out a unique place in the combat sports landscape. The controversies and concerns exist, yes, but as we will see in the next section, there is a strong wave of advocacy in its favor too.

Advocacy for the System

Despite the points of contention surrounding ONE Championship's Hydration & Weigh-In System, significant advocacy remains for its ongoing implementation and potential benefits.

ONE's system finds substantial support from within the organization, its athletes, and even notable personalities operating outside the ONE Championship circle.

ONE's Vice President, Rich Franklin, has been an ardent supporter, expressing public confidence in the system back in 2017. He stated, "We don’t use the term weight cutting because there is no cutting."

Founder of ONE, Chatri Sityodtong, is also proud of the system.

“If you want to fight at the highest level in the world, and you want to fight in the healthiest system, our medical process, obviously, with our hydration, with our fight week CAT scans, with our neurological exams for athletes, is by far the highest standard of any organization in the world, and I'm very proud of that.”

Top-tier athletes in the organization have also thrown weight behind the system. Their continuous participation in bouts under these rules serves as a testament to their acceptance, and perhaps indicative of an acknowledgment that the system leads to strikes that are more equal and bouts that are truly fair and safe.

Interestingly, the advocacy extends beyond the confines of ONE Championship. High-profile personalities such as the famed American comedian and UFC commentator Joe Rogan have voiced support for the weight cutting policy.

Rogan, on his podcast, The Joe Rogan Experience, stated, "The numbers are insane… They got some legit killers… I think it's a big deal… that they don't cut weight. I think it’s a big factor… It's the right way to do it…".

He went a step further, advocating for the UFC to adopt a similar system to rectify harm caused by weight cuts, enhance fighter performance, and ensure frequent, safer bouts.

The potential benefits of the system are undeniable. The primary advantage lies in the increased possibility of improved fighter performance resulting from well-hydrated, properly nourished athletes. Furthermore, regular bouts are more feasible given the reduced recovery time needed in the absence of severe dehydration and subsequent rehydration periods.

ONE Championship Weight Cutting VS UFC Weight Cutting

Of course, the mention of Joe Rogan brings up the comparison with the UFC.

ONE Championship and the UFC have different approaches to weight cutting and weigh-ins in mixed martial arts (MMA). As we've learned, ONE Championship places a strong emphasis on athlete safety and optimal hydration levels.

On the other hand, the UFC follows a different approach to weight cutting and weigh-ins. In the UFC, fighters must weigh in at or below their specific weight on the morning of the day before the fight. Non-title bouts typically have a 1-pound weight allowance, while title fights have a stricter 0.5-pound allowance.

Conor McGregor's extreme UFC weight cut
Conor McGregor's extreme UFC weight cut

If a fighter misses weight, the fight can still proceed, but they may face penalties such as giving up a portion of their salary. Some states, like California, have implemented measures to address extreme weight cutting in MMA. California, for example, has a ten-point plan that includes fines for fighters who miss weight, the introduction of additional weight classes, and increased scrutiny on weight cutting practices.


Operating on fundamentally different principles compared to other combat sports organizations, One's Hydration & Weigh-In System throws the global spotlight on issues surrounding athlete safety, hydration, and weight-cutting. Balancing these complex aspects while ensuring competitive integrity and fairness is no mean feat.

The system's uniqueness, committing to protecting athletes from the drastic and harmful process of weight-cutting by dehydration, has led to both controversy and advocacy.

The tragic incident involving Chinese fighter Yang Jian Bing emphasized the dire need for change. Critics have questioned the system's scientific backing, the alleged ease of manipulating the hydration tests, and hints of fighters continuing weight-cutting practices.

On the other side, the advocacy the system has received from within and outside ONE Championship solidifies its stand. Personalities like Joe Rogan have lauded the methodology and echoed the need for similar interventions in other major combat sports organizations.

In the end, we need to realize that weight-cutting in combat sports is a complex issue, and there isn’t a one-size-fits-all solution. ONE Championship's unique approach shines a spotlight on possible alternates to this complex issue and has profound implications for athletes and audience across the globe.

The conversation around hydration and weight management is evolving, and ONE Championship is certainly leading this change.

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