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Weight Cut

A cut is two processes on two clocks — fat takes weeks, water takes days. The tool that tells you when the math says move up a class.

Every dangerous weight cut is the same arithmetic mistake: treating reversible water weight and real fat loss as interchangeable. Fat comes off at about 0.75% of body weight per week without burning fight muscle; water manipulation can only safely cover roughly 2–5% in the final week even with a 24-hour recovery. This planner splits your cut into both phases, tells you the minimum calendar the physics allows, and prices the rehydration window — 1.5 liters per kilogram lost, plus the glycogen refuel.

Why people use this

Fighters and their corners use it because every dangerous cut is the same arithmetic mistake — treating water and fat as interchangeable. It splits the cut into the two real phases, flags cuts past the ~5% acute ceiling, and shows the calendar the physics actually requires.

How it works

1. Total cut = walking weight − target. The fat phase covers everything above the water ceiling at ~0.75% of body weight per week.
2. The water phase is final-week only: glycogen depletion (1 g glycogen releases ~3 g water), gut-content reduction, sodium taper, fluid restriction — all reversible within hours.
3. Verdict thresholds from sports-medicine consensus: ≤2% acute cut is performance-safe, ~5% is the ceiling with 24h recovery, beyond that the tool says TOO MUCH and shows the weeks you actually need.
4. Recovery math: 1.5 L of fluid per kg lost (ACSM) and 5–10 g/kg of carbohydrate in the 24-hour window to restore glycogen.

Common questions

I walk at 198 lb and fight at 170 lb with 8 weeks. Is that doable?

The math says no, not safely. That is a 14.4% cut; after the maximum ~5% water portion (about 10 lb), you still need 18 lb of fat loss at ~1.5 lb/week — 14 weeks minimum, not 8. At 8 weeks the water cut would have to reach 9.2%, deep into kidney-stress and cardiac-strain territory. The tool will tell you the same thing and show the 14-week plan or the case for fighting at 185.

Why does the water cut have a hard ceiling?

Because dehydration past ~2% of body weight measurably degrades power and cognition, and past ~5% it strains the cardiovascular and renal systems even before you fight. With a 24-hour weigh-in you can restore most of 5%; with a same-day weigh-in you cannot — which is why ONE Championship and some commissions now test hydration at weigh-ins. The recovery window is part of the math, not a detail.

What should I actually do in the final week?

The evidence-based sequence: a low-residue (low-fiber) diet 2–3 days out to empty gut content, a sodium taper after several days of high sodium and high water intake (~100 mL/kg) to trigger a diuresis rebound, then fluid restriction in the last 24 hours — no saunas needed until the final pounds. After weigh-in: 1.5 L per kg lost with electrolytes, 5–10 g/kg of carbs, and no IV fluids (banned above 100 mL/12h by USADA/WADA).

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