IN THIS GUIDE
Why calorie targets often go wrong
Calorie targets usually go wrong when an estimate is treated as exact, the lowest possible intake is chosen, or the plan is changed after one unusual weigh-in. The aim is to create enough of a deficit to see a useful trend without making hunger, recovery and training unnecessarily difficult.
THE SHORT ANSWER
Use the calculator below or your own tracking data, begin with a practical 250 to 600 calorie deficit, and review three consistent weeks before making a small change.
Calories, energy balance and fat loss
A calorie is simply a unit of energy. Food and drink provide energy, and your body uses energy to keep you alive, digest food, move around and train.
If you regularly take in less energy than your body uses, it has to make up the difference from stored energy. That is a calorie deficit, also called negative energy balance, and over time your body weight tends to decrease. If intake is higher than expenditure, you are in a surplus. When the two are roughly matched, weight tends to remain stable.
This does not mean food quality is irrelevant. Protein, fibre and mostly nutritious foods can make a deficit easier to manage and support health, fullness and training. But for fat loss to occur, the overall eating pattern still needs to create a sustained energy deficit.
Your maintenance calories are not a fixed number forever. As body weight and food intake fall, the body may use less energy. Everyday movement, known as NEAT, can decrease, and the thermic effect of food also falls because there is less food to digest. This does not mean your metabolism is broken, and it is not a reason to slash calories in advance. It is why the starting estimate should be tested against your real trend.
Tracking is useful, but it is never perfectly exact. Portions vary, labels describe average values, and normal changes in water, digestion and food weight can hide small changes on the scale. A 50 to 100 calorie deficit can exist mathematically, but for most people it is too small to identify reliably in everyday life. A 250 to 600 calorie deficit usually creates a clearer signal while leaving room for a workable diet.
Evidence & useful reading: Energy balance and metabolic adaptation review · Adaptive thermogenesis systematic review · NHS calorie and weight-loss guidance · UK calorie-labelling accuracy guidance
Choose your starting method
There are two useful ways to choose a starting target. Use the calculator built into this guide for a quick estimate, or use three weeks of your own calorie and weight data. Neither method produces a perfect number on day one, so choose one, stay consistent and refine it from the trend.
Enter your details into the calculator in this guide. It estimates maintenance calories and shows a fat-loss range based on a 250 to 600 calorie deficit. Smaller, lighter or leaner people will often start nearer 250. Larger people may be comfortable nearer 500 to 600. Choose the highest intake that is likely to create progress, then test it for three consistent weeks.
For 21 days, eat normally while tracking your calories as accurately as practical and weighing under similar conditions. Calculate your average calorie intake and average body weight for each week. If weight is broadly stable, your calorie average is a useful maintenance estimate. Subtract roughly 250 to 600 calories to set a fat-loss starting point. If weight was already changing, account for that trend before choosing the target.
Judge the trend, not a single weigh-in
Use three consistent weekly averages before deciding whether the starting target needs to change.
Body weight can move from one day to the next because of water, salt, carbohydrate intake, digestion, training and, for some people, the menstrual cycle. If you weigh several times per week, compare weekly averages. If you weigh once per week, use similar conditions and be especially cautious about reacting to one result. Keep the target unchanged until you have three consecutive weeks of reasonably consistent data, alongside your hunger, energy and training performance.
Make a small adjustment, then test again
If the trend is genuinely flat, change the daily target by 100 to 200 calories and test the new target for another three weeks.
If the trend is not moving down after three consistent weeks and your tracking is reasonably accurate, reduce your daily target by around 100 to 200 calories. Follow the new target consistently for another three weeks before reviewing it again. If weight is falling too quickly or hunger, recovery and training performance are deteriorating, add a small amount back. Make one adjustment at a time.
Common mistakes
Practical checklist
When individual help may be useful
If you need help setting the target around your schedule, coaching can make the numbers easier to apply.
FAT LOSS
