Cutting weight for judo, done safely, means losing weight slowly over several months by eating better rather than eating less, with support from a doctor or a dietitian. Rapid weight loss by dehydration the day before weigh-in is dangerous, and it loses more fights than it wins. For young judokas the question does not even come up: they compete at their natural weight. This article gives general guidance, not a program. Every situation needs a professional opinion.
First question: should you change weight class at all?
Before talking about method, discuss it with your coach. Many judokas want to drop a class because they think they will be stronger there. Sometimes that is true. Often it is not.
A judoka at his natural weight fights with all his energy and a clear head. A judoka who suffered to make weight arrives tired, irritable and slow to react. Plenty of competitors do worse after dropping down than they did in their natural class.
There are good reasons to change: a weight that has shifted for good, a build that suits the next class better, a sports plan that has been thought through. The classes and their limits are listed in our judo weight categories guide.
Moving up is also an option that people forget. A judoka always fighting the top of his class sometimes gains from moving up, building muscle and competing free of the diet.
Young judokas do not cut
No hedging here: a growing child or teenager does not diet for a judo weight class. Their body needs energy to grow. They change class over the seasons as they grow, and that is normal.
A parent or coach who pushes a young athlete to lose weight for a tournament takes a risk with that child's health and with their relationship to food. If a young person's weight is a concern, it is a matter for the family doctor, not for the club.
How to lose weight for judo gradually
For an adult, healthy weight loss follows a few simple principles, adapted with a professional.
Start early
The decision is made months before the target event, not three weeks before. The shorter the deadline, the bigger the temptation to use dangerous methods.
Eat better, not less
Judokas who manage a change of class usually do it by improving their habits. Fewer ultra-processed foods and sugary drinks, vegetables at every meal, enough protein, regular portions. Skipping whole meals leaves you drained and ends in binges. Our article on nutrition for judokas covers the basics of a plate built for training.
Keep training hard
A judoka losing weight must keep training with intensity. If fatigue stops you from doing randori, the method is wrong. Muscle lost does not come back in a week, and muscle is what throws people. A sound strength and conditioning program helps you keep your power.
Get support
A sports medicine doctor or a dietitian who knows weight-class sports is the right person to see. They set a realistic target and a pace that suits your situation. Your judo coach knows your fights, not your metabolism.
Dehydration: the trap to avoid
Rapid weight loss through sweating still circulates in some locker rooms: saunas, plastic suits, restricting fluids, constant spitting. These methods take off water, not fat.
The risks are real:
- loss of strength, endurance and clarity on fight day;
- cramps, fainting, heat illness;
- strain on the heart and kidneys;
- incomplete recovery between weigh-in and the first fight.
Serious accidents have been reported in weight-class sports, wrestling first. In 1997, three American college wrestlers died while cutting weight, which pushed the NCAA to overhaul its weight management rules. No medal justifies that risk. Rules in several sports have changed to limit these practices, for example with extra weight checks on competition day at some events. The details are in our article on the judo weigh-in.
If you are a few hundred grams over the day before, the right call is often to accept it, plan for the next class up at a future event and rethink your preparation.
The days before weigh-in
If you did the work beforehand, the last days need nothing extreme. You are already at your weight. You eat normally, choose easy-to-digest meals, drink and sleep. You check on your own scale that you are under the limit, knowing that scales differ.
After weigh-in, you rehydrate and eat something light but sufficient. Our guide on how to prepare for your first judo competition covers how to organize the day.
Track without obsessing
Weigh yourself at a fixed time, for example in the morning, once or twice a week, not three times a day. Weight naturally moves from one day to the next. The trend over several weeks is what counts.
Also note how you feel in training. Weight loss that comes with worse randori, poor sleep or lasting fatigue means you should ease off. Recovery gets harder when you eat less, so take that into account.
The advice to keep
Choose your class based on your natural weight during normal training, not on an ideal number on paper. If making a class means suffering before every competition, it is not your class. The best judoka you can be is the one who steps on the mat rested, fed and clear-headed. For other health questions linked to training, see our overview of judo injuries.