Home Science Health & Fitness Why Cutting Weight Could Cause Career Ending Kidney Issues For Fighters, And...

Why Cutting Weight Could Cause Career Ending Kidney Issues For Fighters, And How To Avoid It


Frequent dehydration and high protein intake are two factors directly linked to kidney failure. Recently a number of professional fighters have found themselves questioning whether the risks are worth the reward in regards to the weight cut.

Most combat sports require athletes to participate at a pre-determined weight class. Rarely does this mean that the combatants have to add on pounds to make it in to the correct class. Weight-cutting has been an integral part of combat sports since the beginning of sanctioning, and is not losing any momentum. Newer diets, better supplements and more creative methods have given fighters increased options on how to shed the pounds.

Regardless of how the majority of the weight comes off, one would be hard-pressed to find a fighter who doesn’t factor in some element of dehydration and carbohydrate reduction.

“It’s a severe problem with many mixed martial artists because they lose weight rapidly through dehydration,” Dr. Steven Chinn told SciFighting.com. Dr. Chinn is a Urologist with an emphasis in kidney stones based out of Honolulu, Hawaii. According to Dr. Chinn, one-fourth of the body’s cardiac output goes to the kidneys. When the body lacks fluid the blood is thicker and more difficult to move.

“In the short term it may not affect performance, but can have long term effects,” said Dr.Chinn.

The formation of kidney stones occurs when crystals in urine grow faster than they can be flushed from the kidneys. These stones are made of calcium and other materials that collect in large quantities before being removed from the body by the kidneys. This type of waste is water-soluble, and therefore its transportation is highly dependent upon water intake.

“Classically a person is supposed to drink enough water to urinate 2 quarts daily,” said Dr. Chinn. “For me that means I have to drink 2 -2 1/2 gallons a day. If the fighter is dehydrating just for the weight cut day they should be re-hydrating with large amounts of water and be alright for a fight. As far as electrolytes go, people who work out in the gym daily and carry around their Gatorade and sports drinks are really just buying expensive water. Water is typically sufficient.”

Jose Aldo was hospitalized for a broken foot and kidney stones after his victory over Chan Sung Jung at UFC 163 earlier this year. This was not the fighters first bout with kidneys stones, and it is not entirely surprising given that he has been rumored to have a difficult weight-cut in the featherweight division. The hospital visit may assist in making a decision to move up to lightweight.

Aldo is not the first, nor will he be the last fighter to find himself heading to the E.R. in sudden excruciating pain. Symptoms do not usually occur gradually, but instead, come on unexpectedly. Pain is often followed with vomiting and bloody urine. Passing a kidney stone may only require heavy hydration and pain medication, though in other cases surgery may be needed.

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Rodrigo Damm is another Featherweight who is also second guessing the weight cut after being forced out of UFC Fight Night 29 in October due to kidney stones. Damm was still in the early phases of the weight cut, but could not risk the dehydration required in the last week before the fight.

The process of exercising without re-hydrating the body is one many fighters undergo toward the last few days prior to weighing in for competition. Over several years of repeating this same routine every couple of months, the material built up in the kidneys becomes a burden to the body.

Routine dehydration is not the only factor in the formation of kidney stones. High protein diets also are taxing on the kidneys and athletes who use protein supplement may have an increased risk of kidney issues, especially if coupled with dehydration.

“The average person only needs 4-6 ounces of protein daily, which means a lot of people are taking in excess amounts,” said Dr. Chinn.

When protein is ingested and used by the body, protein waste products are created. Normal functioning kidneys can filter this waste. It is then removed from the body in the urine. When kidney function becomes compromised waste accumulates. One early indication of kidney issues is a sense of pain or soreness on the lower to mid back. This is a common feeling during intense dehydration.


Just weeks ago, UFC Welterweight Brian Melancon (7-3-0) announced his retirement from the sport to preserve the remainder of his kidney function. Melancon was scheduled to fight Robert Whittaker at UFC Fight Night 33. He made the announcement via social media.

“It has been announced, I am sad to say that my fight career is over. I have been having kidney problems that have gotten much worse recently and just found out that my kidney function has dropped to 47%. If I continue to train, fight, and cut weight then I run the risk of permanent damage. I have been advised by my Specialist to retire and move on and that is what I will be doing. This is not how I wanted to go out, but I have to believe that God has another path for me. Thanks to all of you who supported me throughout my career.”

Dr. Chinn stresses that important method of maintaining healthy kidney function is hydration throughout training and immediately after weigh-ins assuming dehydration is necessary.

“The likelihood or timeframe at which a fighter may develop kidney issues is depended upon how frequently they dehydrate, for how long and their diet. 50 percent of people with kidney stones will develop them again within five years if they do not change their lifestyle and diet.”