The sight is well known to all mixed martial arts (MMA) fans. A fighter walks onto the stage on a Friday night, waving to the cheering crowd before stepping on a scale. The fighter waits nervously for a few moments while an official checks their weight to see if they have qualified for their chosen weight class.
Weightings are done the day before each MMA fight. They are designed to ensure that both competitors are the same size, which in theory makes for a fair match. Importantly, this is the only time a fighter’s weight is checked by organizers, meaning they only need to be “on weight” for those few seconds. But to ensure they qualify for the weight class they’re competing in, MMA competitors will drastically reduce their body weight for weeks in a process called “weight reduction.”
Weight loss generally occurs in two phases: chronic weight loss (eating less and exercising more frequently for several weeks before the weigh-in), and rapid weight loss (taking extreme measures to lose even more weight in the days before the weigh-in – such as by eating less or fasting and dehydration.
After the weigh-in, the race has started to regain as much weight lost as possible in the 24 hours before the fight, as it is believed to be bigger than your opponent will help you win. This is usually done by eat energy-rich foods high in easily digestible carbohydrates and by consuming more fluids to try rapid rehydration.
Although weight reduction is common in all martial arts, as well as in horse racing, MMA fighters lose more weight than other martial arts athletes, and more cutting in the 24 hours before weighing using extreme methods. The majority of MMA fighters report using saunas or sweat suits to dehydrate themselves to lose weight. Most also miss up to two meals a day (sometimes even fasting all day) while losing weight – and sometimes even eating as little if 300-750 calories per day.
Such energy and fluid limitation can brain and nervous system function and a muscle speed and capacity to work if necessary, which means: more effort is needed complete athletic activities. In addition to these negative effects on performance, there are also important health problems.
A study followed a professional MMA fighter during training preparations for their weight loss and physiological responses for both chronic and rapid weight loss.
During this eight week period, the fighter lost 17 kg, of which 7 kg was mainly due to dehydration in the 36 hours before weighing. This caused a severe reduction in their testosterone production, a sign that the body does not have enough energy to maintain basal hormone function – which is important for all aspects of health. There was also a surge in cortisol (a hormone linked to our stress response), to break down muscle tissue to provide the energy needed for survival.
This fighter also experienced a large increase in both urea and creatinine in their blood, in addition to extremely high sodium levels in the blood, each indicative of renal dysfunction. Together, these findings would prompt this particular fighter to be booked into a hospital bed—not a professional fight.
It’s also highly unlikely that this is an isolated incident – with 43% of athletes at a UK MMA event in 2017, it appeared severely dehydrated prior to competition, suggesting that they had not been able to fully recover their fluids. Worryingly, the fighters in this study also showed hydration and weight loss measurements similar to those reported in fatalities in weight loss in American collegiate wrestling in the 1990s. It was these tragic events that led to widespread rule and culture changes within wrestling, including: changing weighing times and enforce minimum athlete weights in some places to avoid extreme weight loss.
Following on from wrestling, the California State Athletic Commission has taken steps since 2017 to: reduce the amount of weight fighters are allowed to cut off. But despite this, many fighters still take extreme measures to reduce their weight – and with and negative health effects.
Since the introduction of weight classes in MMA in the late 1990s, at least one fighter has formally died linked to weight loss in medical cases. There is also the case of Yang Jian Bing who died in 2015 after heart failure while undergoing severe dehydration to make weight for a professional fight. There are also numerous videos and social media posts showing high level MMA fighters both before and during collapse their official weightings, which indicate the immediate dangers of these practices.
While it is currently uncertain what the long-term effects of repeated weight loss may be, it is: linked to higher levels of obesity after retirement, eating disorders, kidney damage and endocrine dysfunction.
Time for change
Despite the widely held beliefs of athletes and coaches, there’s little to be gained from extreme weight loss — with evidence showing it can actually hinder, not improve, performance. Dates from High Level and Elite MMA Competition shows no difference in the amount of weight lost or regained between winners or losers – with most competitors stepping into the cage and weighing one to two divisions more than their official weigh-in.
Similarly, another study found that MMA fighters who lost more weight lost their fights more often than those that cut less. It has also been shown that fighters who don’t limit energy so severely during the rapid weight loss phase, you have a greater chance of winning.
But changing these practices would require active and preventive involvement of all stakeholders in the industry. As amateur MMA brings more athletes into the sport from a younger age, the International MMA Federation recently established a task force to prevent extreme weight loss and promote safer, more effective weight management practices. Such widespread cultural change will not be quick or easy, but will make a difference to the long-term health of all athletes involved.
