Issue 203

March 2024

Discover the fresh research behind weight cycling in MMA as Ray Klerck unveils the balance between health, fairness, and the competitive edge that may outline the path forward for fighters.

A massively overlooked skill in the MMA game is the art of the weight cut. For some fighters, it’s like squeezing an elephant into skinny jeans, while others master it in a way that makes them seem as if they’ve swallowed a whole other competitor when they step into the octagon. Yoel Romero dwarfed Whittaker in their bout, and he’s rumored to cut 25-40lb before fights, a feat Khabib regularly achieved on his way to GOAT status.

According to experts like Joe Rogan, it’s a practice that courts controversy because it offers such a dramatic performance advantage. “It’s sanctioned cheating, cheating at a much higher scale even than PEDs,” he suggested on his podcast. 

A paper in Sports Medicine argued that weight cutting meets the World Anti-Doping Agency’s (WADA) performance enhancer standards and that it should be prohibited since it can temporarily enhance athletic performance, endangers athletes' health, and violates the spirit of the sport. It’s a risk because plenty of fighters get it so wrong. Just look at the track records of Renan Barão and Anthony Johnson. Weight cycling has become a calculated strategy to gain an advantage over an opponent by competing in a weight class lighter than your natural weight, only to balloon back up in time for the fight. This unique pre-match ritual sets combat sports apart from other athletic disciplines, and a new systematic review on the topic that spanned 25 years has just been published in BMC Sports Science, Medicine and Rehabilitation on the subject. In MMA, unlike in other sports where the leading measures of performance are speed, endurance, or team strategy, weight classes add a layer of complexity. MMA’s classifications aim to match opponents of similar size and strength to ensure fairness, but they have inadvertently birthed a culture of weight manipulation. What follows is everything you need to know about the risks, rewards, and how to cycle weight so when it comes to your next fight night, you’re less mild card and more wild card. 


Dehydration is bad, but it can turn fatal. There have been several tragic combat sport related deaths thanks to extreme weight-cutting practices, which started with Korean Judo Olympian Chung Se-hoon, who died while cutting weight for the 1996 Olympics. More recently, MMA fighter Rondel Clark died in 2017 due to extreme rhabdomyolysis. Even the best can misstep, as a weight cut gone wrong hospitalized Khabib. He claimed he nearly lost his life when scheduled to meet Tony Ferguson at UFC 209.

Some fans may wonder about how these drastic measures may have impacted his decision to retire from the sport relatively early. How do those in charge feel about this? Dana White is very much against it. “No fight is worth dying over,” said White when quizzed about the 2013 MMA-related weight-cut death of Leandro Souza. These deaths underscore the lethal risks associated with extreme weight-cutting measures. Some fight promotions have set rules to avoid these risks, such as ONE Championship’s “walking weight” competition rules. They track athletes via multiple weigh-ins and hydration tests before and during event week. An athlete’s “walking weight” will be tracked regularly throughout the period to keep them safe. This safety-first approach is something that the research backs up as one of the safest ways to cut weight. While many fighters justify cutting weight as short-term, the long-term impact may last a lifetime. 


The research says that a fighter’s weight might yo-yo up and down, but the long-term health issues are less forgiving. Most athletes only drop their body mass by 2-5%, while others reduce it by 5-10% of their initial body weight. Engaging in repeated cycles of rapid weight loss and gain might have a hidden lifetime cost. These issues include potential hormonal imbalances, metabolic adjustments, and a heightened risk for heart health concerns. Techniques often used to hit weight targets, such as intense dehydration and strict dieting, don't just test an athlete's mental limits for a bout; they might also influence kidney function and bone strength over the years. The severity of this damage can be down to how often a combat athlete competes. Some judokas compete over 10 times yearly, and some start as young as 12, seriously damaging their growth potential. The biggest concern is that coaches, who often lack formal nutrition or health-relating training, advise their athletes on how to take part in a weight cut. Moreover, the relentless focus on weight can weave a complex web of psychological challenges, from navigating eating habits to wrestling with body image and the mental strain of weight-class sports. It’s crucial to embrace healthier, science-backed strategies for managing weight in combat sports to safeguard these dedicated athletes' well-being so they don’t become burnt-out husks of their former selves. 


So is Rogan, right? Will a weight cut make you a better athlete if you’re fighting in a division that’s a little lower than your natural weight? Not in all cases, says research in the International Journal of Environmental Research and Public Health. According to this pioneering biomechanical investigation, the advantages and disadvantages of weight cutting vary between people. The study found that although some athletes may perceive their reactions to be faster following weight regain, slower limb movement, decreased striking accuracy, and potentially reduced striking power may counterbalance this advantage. The sample size of this research is small, and this may not be the case for all fighters. The impairments in crucial performance metrics vital to winning an MMA bout could offset the perceived competitive edge gained from weight cycling.

Moreover, other research found that most MMA fighters don’t use a nutritionist to supervise their weight cuts. The health risks associated with extreme weight-cutting practices, such as dehydration, nutritional deficiencies, and the potential for long-term metabolic damage, suggest that the practice may not be worth the potential short-term gains in the ring. Instead, focusing on skill development, strategic training, and maintaining a weight class that is healthy and sustainable for the athlete's body might lead to better long-term MMA success.


Weight-cutting methods often change, and fresh research in the International Journal of Environmental Research and Public Health rounded up the strategies and offers advice on cutting. 

Fluid Manipulation Techniques: Athletes use "water loading" techniques followed by sudden fluid restriction. This method involves consuming large amounts of water (7-10 L/day) for several days before drastically reducing fluid intake, promoting diuresis and rapid weight loss.

Dietary Adjustments: Athletes might employ strategies like reducing carbohydrate intake to lower glycogen stores and the water bound to glycogen, leading to weight loss. Low-fiber diets are also typical to minimize gastrointestinal content. However, extreme calorie restriction or improper dieting can lead to severe dehydration and other health risks.

Active and Passive Sweating: Utilizing saunas, wearing sweat suits, or engaging in intensive workouts to induce sweating are standard practices. These methods aim to shed water weight quickly but can significantly dehydrate the athlete.

Supplementation and Pharmacological Aids: Despite the potential health risks and prohibition by many sports governing bodies, athletes report using diuretics, laxatives, or other pharmacological agents to promote fluid loss.


The studies reviewed show mixed outcomes regarding the effect of rapid weight loss on athletes' performance. While some strategies, particularly those resulting in up to 5% body weight loss, do not suck the life out of your overall athleticism, more substantial weight losses can chuck a bucket of cold water on your strength, endurance, cognitive functions, and mood states. That doesn’t sound like the person who gets their hand raised at the end of a fight. Dehydration strategies and extreme calorie restriction can alter your hormonal balances, blood, and urine parameters, and even the kinematics of movements. Thanks to this, post-weigh-in recovery strategies have become crucial. Adequate rehydration and nutrient intake are mandatory for offsetting the negatives around weight loss. The studies suggest that a recovery period of at least 24 hours is generally required to facilitate partial recovery. However, complete physiological and performance recovery may need more than 48 hours.


To be the fighter you were before your weight cut, your losses should not exceed 3% to 5% of body weight, and athletes should allow at least 24 hours for rehydration and recovery. Progressive weight loss over several weeks will always be the gold standard, especially for competitions spanning multiple days or rounds. Careful planning and supervision must emphasize the weight-cutting processes needed to sidestep nasty health outcomes and performance decrements. The research underscores the complexity and risks linked to weight cutting. While athletes can implement certain weight loss methods without significantly impairing performance, the potential health risks require a cautious, well-informed approach. This is the playbook for weight cycling that hits different, in a good way. 


The systemic review calls for a reevaluation of weigh-in protocols, suggesting that fight promotions should move the weigh-ins closer to the start of the competition as this might lower the extremes of weight cycling. By limiting the time available for athletes to regain weight, organizers can encourage more natural competition weights, enhancing athlete safety and preserving the integrity of the sport. Promotions want their fighters to be healthy, but the impact of weight cycling has a big question mark hanging over it. A 2024 paper in the journal Metabolites found that in combat sports, the short-term effects of rapid weight loss, such as a reduced metabolic rate and alterations to insulin and leptin levels, might create more pronounced metabolic disturbances that occur during weight regain, such as insulin resistance. These effects may contribute to metabolic syndrome or other metabolic dysfunctions over time. This is a scientific way of telling you to imagine that your body is running like a phone app. When you lose weight quickly, it's like forcing it to update without permission. Your metabolism hits the snooze button, saving energy just in case, and hormones like insulin and leptin start glitching, thinking, "What's the plan here?" Then, when you gain the weight back, it's not a simple reset. Your body overcompensates, leading to potential metabolic mishaps, like when an app starts crashing because it can't handle the new updates. So, rapid weight loss and regain is like a confusing software update for your body, potentially leading to bigger bugs in the system down the line. A smoother, more gradual update might keep the system running more smoothly. However, with these weight cuts' performance-enhancing benefits, the quest for solutions is ongoing. By continuing the research and having an open dialogue, the MMA community can work toward a future where competition balances health and fairness. In the octagon of life, the toughest opponent might just be your next weigh-in, but the powers that be are very clear about carving a healthier path for fighters whose performance we can enjoy for years to come.