Safety & health

Last updated · 29 August 2026

What this app can and cannot do for you — and what it can do to you. The one document here worth reading before you use the plan.

This page is part of the terms of use. It is written plainly because it is the only page here that can change what happens to your body.

What the numbers actually are

Every target in Kalv is an estimate produced by an equation from what you typed in: your weight, your height, your age, your discipline, your training load, your weigh-in date. It is not a measurement. Nobody weighed your food, nobody analysed your metabolism, and nothing in the app has seen you.

Which means the error is real and it stacks: energy equations are population averages and individuals sit either side of them; scanned or barcode-matched food data is an estimate of an estimate; and a training load you described as hard may be nothing like the one the model assumed. Treat the numbers as a starting point you adjust with experience, not as a prescription.

Cutting weight is the risky part, and it is the part you own

Rapid weight loss before a weigh-in — restricting food, restricting fluid, sweating it out — is normal practice in combat sport and it is where the harm in this sport happens outside the ring. The documented risks include heat illness, kidney injury, cardiovascular strain, electrolyte disturbance, impaired thermoregulation, worse decision-making and slower reactions, reduced power, and a brain that is more vulnerable to impact when dehydrated. Athletes have died doing it.

Kalv plans food and drink. It does not design a water cut, a sauna protocol, a sweat session or a rehydration schedule, and if you are running one it does not know and cannot account for it. Anything of that kind belongs with a doctor and a qualified coach who can see you, not with an app.

If the plan asks for a rate of loss you cannot reach without doing something drastic, the honest reading is not that you need to try harder. It is that the target weight, or the weight class, is wrong. Changing division is a legitimate answer and it is one the app will never give you.

Nobody is watching your log

There is no supervision behind this app. No human at Kalv reads your entries, nothing raises an alarm if your weight falls fast, if you stop eating, or if you log nothing for a fortnight. The app cannot tell the difference between a well-run week and a crisis. Do not treat its silence as reassurance, and do not treat a green ring as a medical opinion.

Eating disorders

Weight-class sports carry a higher rate of disordered eating than most, and calorie tracking is a known trigger for people who are vulnerable to it. This is the plainest sentence on this site: if you have or have had an eating disorder, this app is not for you, unless someone treating you has said otherwise.

Stop using it, and talk to someone, if counting starts to feel compulsory, if a missed target ruins your day, if you hide what you eat, if you eat in secret and then compensate, or if the number on the scale has started deciding how you feel about yourself.

In France, Anorexie Boulimie Info Écoute — 09 69 325 900 is a free, anonymous line staffed by specialists (Monday, Tuesday, Thursday and Friday afternoons). Elsewhere, your doctor or your national health service can point you to the equivalent. Asking is not a weakness in a sport built on managing weight; it is the most professional thing in it.

When you should not use Kalv without a doctor

• You are under 18 — in which case you may not use Kalv at all, and no conversation with a doctor changes that: it is a condition of the terms. Cutting weight in a growing athlete is a medical decision, not an app decision, and many federations regulate it.
• You are pregnant or breastfeeding.
• You have diabetes, kidney disease, heart disease, high blood pressure, a thyroid condition, or any condition affected by body weight, nutrition or hydration.
• You take medication that affects fluid balance, appetite or metabolism — diuretics included.
• You are recovering from a concussion, an injury or an illness.

If something goes wrong, stop and get help

Call your local emergency number — 15 or 112 in France — if during or after a cut you experience confusion or disorientation, fainting, chest pain, an irregular heartbeat, severe cramping, persistent vomiting, no urine for many hours, or a headache that will not go. Do not wait for the weigh-in to see whether it passes. No bout is worth it, and no bout is worth the one after it either.

Your federation's rules are yours to know

Weigh-in procedure, hydration testing, permitted rehydration, minimum weight and the rest are set by your federation and your commission, and they differ. Kalv does not know your rulebook and does not check it. Following the app is not a defence to breaking a rule.

Where this leaves us

You are the athlete. Every decision to eat, drink, cut, train, compete or withdraw is yours and — for a minor — your parents' and your coach's. Kalv gives you a number and a picture of your week; it takes no responsibility for what you do with them, and it could not, because it is not in the room. The limits of our liability are in section 12 of the terms of use.

Questions about anything on this page: support@kalv.app.