How to Rehydrate After Weigh-In: 24-Hour Plan

Contents

To rehydrate after the weigh-in, start right away with a sodium-containing drink in regular portions, not a litre of plain water in one go, then add fast, low-fibre carbohydrates and move on to salty, carb-rich meals. The ISSN position stand recommends oral rehydration solutions at about 1–1.5 litres per hour immediately after the weigh-in, followed by fast-acting carbohydrates at up to 60 g per hour (Ricci et al., 2025). How much you can fully recover depends on how much you cut and how many hours you have until the fight.

The cut is only half the job. A perfect weigh-in followed by a sloppy refuel still puts a flat, drained fighter in the ring. This guide gives you a timeline you can follow.

How much time do you have between weigh-in and fight?

Your recovery window decides how hard you can cut and how much you can put back. In professional MMA with a day-before weigh-in, roughly 24–36 hours remain before competition, which the ISSN describes as adequate time to rehydrate and refuel (Ricci et al., 2025). Olympic combat sports weigh in anywhere from 3 to 24 hours before competing (Reale et al., 2017).

• 24+ hours: enough to replace most fluid and refill glycogen, if the cut was moderate.
• 4–12 hours: fluids and light carbs, but your stomach sets the pace.
• Under 4 hours: the ISSN notes that rapid weight loss has diminished value when the window to replace fluid and electrolytes is this short (Ricci et al., 2025). A big cut rarely pays off here.

Some promotions don’t allow the classic dehydrate-then-rehydrate model at all. ONE Championship runs a combined hydration test and weigh-in 24–48 hours before the event, and athletes must show a urine specific gravity of 1.025 or lower before they are allowed to weigh in (ONE Championship). See how much weight you can cut before you plan your number.

How much weight do fighters regain after weigh-in?

Real-world regain is usually a few percent of body mass, but it varies hugely by sport. Elite judoka regained 2.3 % (men) and 3.1 % (women) of body mass in the 15–20 hours between weigh-in and their first fight (Reale et al., 2016). Elite boxers at a national championship were 2.1 % (men) and 1.5 % (women) heavier before their bouts than at the official weigh-in (Reale et al., 2017).

The ISSN recommends that post-weigh-in rehydration and refuelling protocols aim to regain at least 10 % of body mass to limit performance losses from rapid weight loss (Ricci et al., 2025). Read that as a guide for fighters who cut big with a 24–36 hour window, not a target to chase: if you only cut 3 %, there is nothing like 10 % to regain, and you should not try to force it.

Fluids and sodium: how to drink after the weigh-in

Drink in steady portions with sodium, not a huge bolus of plain water. Salt helps your body hold on to the fluid instead of flushing it out as urine.

What the guidelines say:

• Volume: replace about 125–150 % of the fluid lost through sweat. That is realistic in a 24–36 hour window but often impractical with same-day weigh-ins (Ricci et al., 2025). The ACSM statement also uses ~150 % of the fluid deficit, to cover ongoing urine and sweat losses (Burke et al., 2021).
• Start: if you are more than 3 % dehydrated, the ISSN suggests a conservative first bolus of 300–500 mL right after the weigh-in, then ~240–350 mL every 30 minutes to keep fluid moving through the stomach (Ricci et al., 2025). The ACSM statement gives a larger example bolus of about 10 mL/kg, followed by smaller volumes at regular intervals (Burke et al., 2021). Start at the conservative end if your stomach is sensitive.
• Sodium: use an oral rehydration solution (ORS) when you are more than 3 % dehydrated. Below 3 %, a regular sports drink gives adequate fluid retention (Ricci et al., 2025). Salty foods count too (Burke et al., 2021). More on this in our guide to electrolytes and weight cutting.
• Monitoring: track urine frequency and colour and step on the scale as you go (Ricci et al., 2025).

Worked example (arithmetic only): a 75 kg fighter who sweated off 3 kg. 150 % of 3 kg is about 4.5 litres over the whole window. At 1–1.5 L per hour, most of that could go in during the first few hours, with the rest sipped through the evening and fight day.

Carbohydrates: refilling your glycogen

How many carbs you need depends on how much you depleted. Fighters who ran significant glycogen depletion in fight week may need 8–12 g of carbohydrate per kg after the weigh-in. For a more modest restriction, 4–7 g/kg may be enough (Ricci et al., 2025).

Glycogen binds water, about 2.7 g of water per gram of glycogen (Ricci et al., 2025), so refilling your carb stores also brings back part of the water weight.

• Start with fast-acting carbs at up to 60 g per hour after the first ORS (Ricci et al., 2025).
• The ACSM statement suggests about 1 g/kg per hour early in recovery, in frequent small feedings, and adding ~20–25 g of high-quality protein to carb-rich meals (Burke et al., 2021).
• Carb-containing drinks count toward both your fluid and your carb targets.

For a 75 kg fighter, 8–12 g/kg works out to 600–900 g of carbohydrate across the whole window, and 4–7 g/kg to 300–525 g.

Rehydration timeline: an example 24-hour plan

The table below is an example for a day-before weigh-in, built from the ISSN and ACSM guidance. Adjust volumes to your size and how much you cut, and rehearse it in camp.

Time after weigh-in	Fluids	Sodium	Food and carbs
0–30 min	300–500 mL ORS (ACSM example: up to ~10 mL/kg)	ORS if more than 3 % dehydrated	Carbs from the drink only
30 min–2 h	~240–350 mL every 30 min, around 1–1.5 L/h	ORS or sports drink	Fast carbs, up to ~60 g/h. Avoid trigger foods
2–6 h	Keep sipping; switch to sports drink or water with meals	Salt your food	First real meal: rice, potatoes, pasta, white bread, plus ~20–25 g protein
6 h–bedtime	Drink to thirst; check urine colour and weight	Normal-to-salty meals	More carb-rich meals toward your total (4–7 or 8–12 g/kg)
Fight day	Small, regular sips	Normal	1–4 g/kg carbs from familiar foods; lighter meals as the fight nears

Fight-day numbers come from the ISSN, which gives the example of a 70 kg athlete with a 6-hour window eating 210–280 g of carbohydrate (Ricci et al., 2025).

What to eat after the weigh-in, and what to avoid

Eat familiar, easily digested carbohydrates, and keep fibre and fat low. Fibre slows gastric emptying and can cause discomfort, and big portions of protein or fat can also delay gastric emptying (Ricci et al., 2025).

Good choices (examples from the ISSN): potatoes and sweet potatoes, rice, flour-based foods like sourdough, pancakes and pasta, plus low-volume snacks such as bars, pretzels, applesauce and dates (Ricci et al., 2025).

Limit in the first 0–2 hours: the ISSN suggests avoiding or minimising coffee, citrus fruits and juices, tomato products, chocolate, peppermint, garlic and onion, and fatty, spicy or fried food, which can delay gastric emptying or worsen reflux and bloating (Ricci et al., 2025).

Never try something new. Fight day is not the time to experiment.

Can you fully recover in 24 hours?

Not always. Research on weight-cut recovery is mixed: some studies found 24 hours insufficient to restore hydration status, while others saw most hydration markers back to baseline after 24 hours (Barley et al., 2019). The ACSM statement also warns that it may not be possible to fully restore fluid losses in the time available, so you should prioritise what matters most for your sport (Burke et al., 2021).

The practical lesson: the smaller the cut, the more reliably you recover. A good refuel can’t rescue a cut that was too big. That is decided weeks earlier, in how you cut weight for the fight.

The most common rehydration mistakes

1. Chugging plain water. Without sodium, more of it leaves as urine.
2. Drinking too much at once. Big volumes can cause bloating and discomfort. Portions every 30 minutes work better.
3. Heavy, fatty meals. Pizza and burgers sit like a brick right when you need fast fuel.
4. Loads of fibre and raw vegetables. Save them for after the fight.
5. No dress rehearsal. Test your refuel after a hard session in camp. If you water load or use the sauna, plan the refuel alongside it.

MyFightPrep helps you plan and track your refuel hour by hour after the weigh-in, including fluids, electrolytes and carbohydrates — free.

Important

This guide is general information, not medical advice. Rehydration does not guarantee that your body has fully recovered from a cut, and severe dehydration can be dangerous. If you are under 18, new to the sport or unsure, plan your cut and refuel with your coach and a doctor or sports dietitian. Stop and seek medical help if you experience dizziness, confusion, fainting, severe cramps, a racing heart or very little or dark urine.

Frequently asked questions

What is the fastest way to rehydrate my body completely after a weigh-in?

Drink a sodium-containing oral rehydration solution in regular portions rather than chugging plain water. The ISSN position stand suggests about 1 to 1.5 litres per hour right after the weigh-in, starting with a 300 to 500 mL bolus and then roughly 240 to 350 mL every 30 minutes.

What is the best thing to eat after weigh-ins?

Familiar, easily digested, high-glycemic carbohydrates that are low in fibre and fat: white rice, potatoes, pasta, white bread or sourdough, pancakes, pretzels, applesauce and dates. Add a moderate portion of protein, and avoid fatty, fried, spicy or high-fibre food in the first hours.

How long does it take to fully rehydrate after dehydration?

It depends on how much water you lost. Replacing 125 to 150 % of the fluid lost is realistic in a 24 to 36 hour window, but some research has found that even 24 hours is not always enough to restore hydration status after a weight cut.

How much fluid should I drink after a weigh-in?

Sports nutrition guidelines suggest replacing about 125 to 150 % of the fluid you lost, spread over the whole recovery window. For a fighter who sweated off 3 kg, 150 % is about 4.5 litres, not in one go but across the hours before the fight.

Sources

This guide is based on the works below. Numbers in the text refer to them.

1. Ricci AA, Evans C, Stull C, Peacock CA, French DN, Stout JR, et al. (2025). International Society of Sports Nutrition Position Stand: Nutrition and Weight Cut Strategies for Mixed Martial Arts and Other Combat Sports
2. Burke LM, Slater GJ, Matthews JJ, Langan-Evans C, Horswill CA (2021). ACSM Expert Consensus Statement on Weight Loss in Weight-Category Sports
3. Reale R, Slater G, Burke LM (2017). Individualised Dietary Strategies for Olympic Combat Sports: Acute Weight Loss, Recovery and Competition Nutrition
4. Reale R, Cox GR, Slater G, Burke LM (2016). Regain in Body Mass After Weigh-In is Linked to Success in Real Life Judo Competition
5. Reale R, Cox GR, Slater G, Burke LM (2017). Weight Regain: No Link to Success in a Real-Life Multiday Boxing Tournament
6. Barley OR, Chapman DW, Abbiss CR (2019). The Current State of Weight-Cutting in Combat Sports
7. ONE Championship (2026). Martial Arts: weigh-in and hydration testing rules