Adding to this site’s archived combat sports safety studies, a case study was recently published in the International Journal of Sport Nutrition and Exercise Metabolism documenting negative health and performance consequences from rapid extreme weight cutting.

In the Study, titled “Case Study: Extreme Weight Making Causes Relative Energy Deficiency, Dehydration and Acute Kidney Injury in a Male Mixed Martial Arts Athlete” the author obtained regular assessments of body composition, resting metabolic rate (RMR), VO_{2  Peak} and blood clinical chemistry to assess endocrine status, lipid profiles, hydration and kidney function of a mixed martial artist undergoing a typical weight cut.  The cut included 7 weeks of diet with reduced calorie intake, 5 days of water loading and lastly fasting and dehydration.  This resulted in an 18.1% body mass decline.

The author documented a host of negative consequences including relative energy deficiency, inability to complete performance tests, alterations to endocrine hormones, hypercholesterolemia, hypernatremia and acute kidney injury.

The study can be found here with the abstract reading as follows:

The aim of the present case study was to quantify the physiological and metabolic impact of extreme weight cutting by an elite male MMA athlete. Throughout an 8-week period, we obtained regular assessments of body composition, resting metabolic rate (RMR), VO_2peak and blood clinical chemistry to assess endocrine status, lipid profiles, hydration and kidney function. The athlete adhered to a “phased” weight loss plan consisting of 7 weeks of reduced energy (ranging from 1300 – 1900 kcal.d^-1) intake (phase 1), 5 days of water loading with 8 L per day for 4 days followed by 250 ml on day 5 (phase 2), 20 h fasting and dehydration (phase 3) and 32 h of rehydration and refuelling prior to competition (phase 4). Body mass declined by 18.1 % (80.2 to 65.7 kg) corresponding to changes of 4.4, 2.8 and 7.3 kg in phase 1, 2 and 3, respectively. We observed clear indices of relative energy deficiency, as evidenced by reduced RMR (-331 kcal), inability to complete performance tests, alterations to endocrine hormones (testosterone: ❤ nmol.L^-1) and hypercholesterolemia (>6 mmol.L^-1). Moreover, severe dehydration (reducing body mass by 9.3%) in the final 24 hours prior to weigh-in induced hypernatremia (plasma sodium: 148 mmol.L^-1) and acute kidney injury (serum creatinine: 177 μmol.L^-1). These data therefore support publicised reports of the harmful (and potentially fatal) effects of extreme weight