How to use your TDEE for weight loss, maintenance, or gain

Once you know your TDEE, the next step is simple in principle and harder in practice: eat a little less than it to lose weight, about the same as it to maintain weight, or a little more than it to gain weight. The calculator on this site suggests 500 calories below TDEE for a cut and 500 above for a bulk. Those round numbers are a starting point, not a rule, and this guide explains why.

A deficit of 500 calories a day works out to about 3,500 calories a week, which is often quoted as roughly half a kilogram of body fat. In real life the maths is messier. Water weight shifts daily, activity changes as you get lighter, and hunger grows as a deficit continues. A reasonable expectation is slow, uneven progress — perhaps a quarter to half a kilogram a week for many people — rather than a straight line on a chart. If you are losing much faster than that without trying, or you feel constantly exhausted, the deficit is probably too large.

Maintenance is the goal most people underestimate. Eating at your TDEE sounds like doing nothing, but for someone who has lost weight, maintenance is an achievement in itself, because a smaller body has a smaller TDEE than it did before. The number that maintained your weight at 90 kilograms will not maintain it at 80 kilograms. Recalculate every few months, or whenever your weight has changed by several kilograms and settled there.

Gaining weight well is also slower than people expect. A surplus of 500 calories a day, combined with resistance training, is a common starting point for building muscle with less fat gain than a very large surplus would cause. Eating far above TDEE mostly adds fat, not muscle, because muscle can only be built so fast. Protein intake and training matter at least as much as the calorie number itself, and this site deliberately does not prescribe protein targets, because those depend on your training, health and preferences.

Three mistakes show up again and again. First, people pick an activity factor that describes the person they wish they were, not the person they are. Be honest about your last two weeks, not your best week. Second, people treat the calculator number as exact. It is an estimate with a margin of error of several hundred calories, so judge it by what happens over weeks, not by one day's scale reading. Third, people change everything at once — new diet, new training, new sleep schedule — and then cannot tell what worked. Change one thing, watch for two weeks, then decide.

A practical routine looks like this. Calculate your TDEE, pick a target 300 to 500 calories below or above it, track your food honestly for two weeks, and weigh yourself a few times a week under similar conditions. If the trend moves the way you want, keep going. If it does not move at all after three weeks, adjust by 200 calories and try again. If you feel unwell, stop and get professional advice. Weight is only one measure of health, and a calculator cannot see your energy, sleep, mood or blood work.

This is general information only, not medical advice. If you are under 18, pregnant, managing diabetes, a thyroid condition, an eating disorder or any other medical issue, do not set a calorie target from a website alone. Start with a professional, and use tools like this one to understand the conversation, not to replace it.

Next step: calculate your own TDEE, or read what TDEE actually is.