ISSN Issues First Evidence-Based Nutrition Guide for MMA and Combat Sport Athletes

Combat sports including MMA, boxing, wrestling, judo, and Brazilian jiu-jitsu involve weight-class competition, making nutritional strategy and weight management central to athlete preparation and safety. Despite the sport's rapid global growth—epitomized by the UFC generating over a billion dollars annually—evidence-based nutritional guidance specifically tailored to combat athletes has been lacking. This ISSN position stand represents the first formal attempt to consolidate the available science into actionable recommendations.

The authors conducted a systematic literature review across PubMed, MEDLINE, and Google Scholar using terms spanning combat sports, acute weight cutting, bioenergetics, glycogen status, hydration, and nutrient timing. Studies were categorized by four phases of combat sport preparation: general preparation (off-camp), fight camp, fight week, and post-weigh-in recovery. A critical structural insight in the paper is that weigh-in timing dramatically dictates permissible strategies—sports with 24–36-hour windows (professional MMA, boxing) allow aggressive acute water loss and robust rehydration, while same-day weigh-in sports (wrestling, Brazilian jiu-jitsu) afford only 1–2 hours of recovery, necessitating a greater reliance on actual fat loss rather than acute dehydration.

Bioenergetically, MMA is characterized as a mixed-demand sport: bouts lasting beyond 4 minutes derive over 70% of energy from aerobic pathways, while explosive bursts rely on the ATP-PCr and glycolytic systems. This dual demand shapes macronutrient needs across all phases. During off-camp, athletes are advised to maintain body mass 12–15% above their target weight division. Minimum macronutrient floors during fight camp are specified: carbohydrates 3.0–4.0 g/kg, protein 1.2–2.0 g/kg, and fat 0.5–1.0 g/kg/day. Protein is especially emphasized to preserve lean mass during caloric restriction, while carbohydrates support training performance.

For fight week, the position stand provides specific guidance on safe rates of body mass reduction: 6.7% at 72 hours, 5.7% at 48 hours, and 4.4% at 24 hours before weigh-in. Glycogen depletion through exercise and carbohydrate restriction can facilitate 1–2% body mass loss, and low-fiber intake below 10 g/day for 4 days adds equivalent losses from reduced gut content. Acute water loss via sauna, hot water immersion, and compression wraps is endorsed within a supervised 2–4% body mass range within 24 hours of weigh-in. Sodium restriction combined with water loading is highlighted as effective for inducing polyuria.

Post-weigh-in recovery protocols prioritize oral rehydration solutions at 1–1.5 liters per hour with 50–90 mmol/dL sodium, followed by fast-acting carbohydrates at ≤60 g/hour. Athletes who underwent significant glycogen depletion may need 8–12 g/kg carbohydrate intake, while those with modest restriction may need only 4–7 g/kg. The overall goal is to regain at least 10% of body mass before competition to mitigate performance decrements. Supplementation with creatine, beta-alanine, HMB, and caffeine is supported across preparation and competition phases. The authors note that the long-term health consequences of repeated weight cycling in combat athletes remain poorly understood and warrant further investigation.