How to make weight safely and effectively — a complete protocol for Kun Khmer fighters
Weight cutting carries real health risks, including kidney damage, heat stroke, cardiac arrhythmia, and in extreme cases, death. Multiple combat sports athletes have died from aggressive weight cuts. Never cut weight without the supervision of an experienced coach or nutritionist. If you experience any of the warning signs listed below, stop the cut immediately and seek medical attention. No fight is worth your life or long-term health.
A systematic approach to losing 3-5 kg over four weeks, with a final water cut of 1.5-3 kg
Calories: Reduce daily intake by 300 kcal from maintenance
Carbs: Reduce to 4 g/kg from training-level intake
Protein: Maintain at 2.0-2.2 g/kg (do not reduce protein)
Fat: Reduce to 0.8 g/kg minimum
Water: Normal intake — 35-40 ml/kg per day
Training: Full training volume. No changes to training schedule.
Begin by eliminating empty calories: sugary drinks, fried snacks, alcohol. This alone often accounts for the initial caloric reduction. Track your weight every morning after using the toilet and before eating.
Calories: Reduce daily intake by 400 kcal from maintenance
Carbs: Reduce to 3.5 g/kg on rest days, 4.5 g/kg on training days
Protein: Maintain at 2.0-2.2 g/kg
Fat: Maintain at 0.8-1.0 g/kg
Water: Increase to 45 ml/kg per day (water loading begins)
Training: Full training volume. Monitor energy levels during sparring.
Begin carbohydrate cycling — higher on training days, lower on rest days. Start water loading at 45 ml/kg to prime the body for the water cut in week 1. Reduce sodium intake slightly by avoiding added salt and high-sodium sauces.
Calories: Reduce daily intake by 500 kcal from maintenance
Carbs: Reduce to 3 g/kg on rest days, 4 g/kg on training days
Protein: Maintain at 2.0-2.2 g/kg
Fat: Maintain at 0.8 g/kg
Water: Increase to 50 ml/kg per day (peak water loading)
Training: Begin tapering volume. Reduce sparring intensity. Maintain pad work and technique.
Peak water loading this week teaches your body to excrete fluid at a higher rate, which will be leveraged during the water cut. Continue reducing sodium gradually. Monitor mood, sleep quality, and training performance — if any deteriorate significantly, ease back on the deficit.
Calories: Maintain the 500 kcal deficit. Do not further reduce.
Carbs: Reduce to 2 g/kg (low carb to deplete glycogen and shed water)
Protein: Maintain at 2.0 g/kg
Fat: Maintain at 0.8 g/kg
Water: Monday-Tuesday: 50 ml/kg. Wednesday: 25 ml/kg. Thursday: 15 ml/kg. Weigh-in day: sips only.
Training: Light technical work only. No sparring. Short pad rounds for sharpness.
This is where the water cut happens. The body, accustomed to excreting high volumes of water from the loading phase, continues flushing fluid even as intake drops. Combined with low carbohydrates (each gram of glycogen holds 3g of water), this produces the final weight loss. This must only be done when there is adequate time to rehydrate before the fight.
The water cut exploits a physiological principle: when you consistently drink large volumes of water, your body increases its rate of fluid excretion through urine. By loading water for 7-10 days and then sharply reducing intake, the body continues excreting at the elevated rate for 24-48 hours, producing a net loss of body water.
A properly executed water cut should remove no more than 3-4% of body weight. For a 70 kg fighter, this means a maximum of 2.1-2.8 kg through water manipulation. Combined with the 1.5-2 kg lost through the dietary deficit in weeks 1-3, this allows a total cut of approximately 4-5 kg from walking weight.
Days 10-7 before weigh-in: 50 ml/kg (3.5L for 70kg fighter)
Days 6-4 before weigh-in: 50 ml/kg (3.5L for 70kg fighter)
Day 3 before weigh-in: 25 ml/kg (1.75L for 70kg fighter)
Day 2 before weigh-in: 15 ml/kg (1.05L for 70kg fighter)
Day 1 (weigh-in day): Sips only until after weigh-in
Restoring fluid, electrolytes, and glycogen after the cut
Immediately after weigh-in
500ml of electrolyte drink within the first 15 minutes. Do not chug — steady sipping prevents nausea. The solution should contain sodium (1,000-1,500 mg/L), potassium, and a small amount of glucose.
0-2 hours post weigh-in
Alternate between ORS and coconut water. Begin eating small, easily digestible carbohydrate-rich foods: white rice, bananas, rice porridge (bobor). Aim for 1-2 g/kg of carbohydrates in this window.
2-4 hours post weigh-in
Bai sach chrouk or plain rice with grilled chicken. Avoid heavy, greasy, or high-fiber foods that slow gastric emptying. Continue drinking fluids — target another 1 liter. Add fruit for potassium (banana, coconut water, mango).
4-8 hours post weigh-in
Second moderate meal. Total fluid intake should reach 1.5x the weight lost during the cut. If you cut 3 kg of water, aim to drink at least 4.5 liters total by this point (including fluids in food). Include some salty foods to help retain fluid.
8-12 hours post weigh-in
Familiar, well-tolerated meal. Moderate portions — do not overeat. Amok trey with rice or a similar balanced Cambodian meal. Stop eating 3-4 hours before the fight to allow complete digestion.
Morning of fight
Small portion of rice with a light protein source. Sip water and electrolytes. Avoid anything new or unusual. Many fighters prefer kuy teav or bobor (rice porridge) — familiar, easy to digest, and comforting.
Persistent headache that does not resolve with hydration
Moderate
Dizziness or lightheadedness when standing up
Moderate
Dark amber or brown urine, or no urination for 8+ hours
Severe
Rapid heart rate (>100 bpm) at rest
Severe
Muscle cramping that does not resolve with stretching
Moderate
Confusion, disorientation, or difficulty concentrating
Emergency
Extreme irritability, mood swings, or emotional instability
Moderate
Chest pain or difficulty breathing
Emergency
Loss of coordination or balance
Severe
Fainting or near-fainting episodes
Emergency
Body temperature above 38.5°C (101.3°F)
Severe
Vomiting or inability to keep fluids down
Severe
Emergency signs require immediate medical attention. Stop all weight cutting activity, begin rehydrating, and seek a medical professional. Severe signs mean you should stop the cut, rehydrate, and reassess whether you can safely make weight. Consider moving up a weight class. Moderate signs indicate you are approaching your limit — slow down the cut and monitor closely.
Based on walking weight with a 4-week preparation period
| Walking Weight | Safe 1-Class Cut | Safe 2-Class Cut | Max Total Cut |
|---|---|---|---|
| 52 kg | 50 kg | 48 kg | 4 kg (7.7%) |
| 57 kg | 54.5 kg | 52 kg | 5 kg (8.8%) |
| 63 kg | 60 kg | 57 kg | 6 kg (9.5%) |
| 70 kg | 67 kg | 64 kg | 6 kg (8.6%) |
| 77 kg | 73.5 kg | 70 kg | 7 kg (9.1%) |
| 84 kg | 80 kg | 76 kg | 8 kg (9.5%) |
These guidelines assume a full 4-week preparation with proper water loading and dietary manipulation. Attempting to cut more than 8-10% of body weight is strongly discouraged, regardless of the time available. Fighters who consistently struggle to make weight should consider competing at a higher weight class — fighting at your natural weight often produces better performance than fighting depleted and dehydrated.
Most fighters can safely cut 5-7% of bodyweight over four weeks combined with a small final water cut. A 70 kg fighter could realistically make 65 kg using a 4-week gradual cut plus 1-2 kg water cut in the final 48 hours. Cuts beyond 10% of bodyweight carry serious medical risk and are strongly discouraged.
Kun Khmer uses 18 weight classes from Mini Flyweight (47.6 kg / 105 lbs and below) to Super Heavyweight (over 95.3 kg / 210 lbs). Your competition weight is the upper limit you can hit on weigh-in day, not your walking-around weight. Most fighters cut 3-7% of body weight in the week before a fight. Use the weight class calculator on the rules page to find your class.
Your competition weight class is determined by your post-cut weight at weigh-in, not your daily walking-around weight. Cambodian KBSF and ONE Championship use 18 weight classes from Mini Flyweight (47.6 kg / 105 lb upper limit) to Super Heavyweight (95.3+ kg / 210+ lb). Use the Weight Class Calculator on the rules page to find your division based on your current weight and realistic cut.