How many calories should I eat to lose weight? (UK guide)

Most adults lose weight steadily on a target of roughly 1,500 to 2,000 kcal a day, but the honest answer is that it depends on you. To find your own number, work out how many calories you burn in a day, then eat about 500 kcal less than that. That gives a loss of around 0.5kg a week, which is a pace most people can actually keep up.

Here is how to do the maths yourself. It takes about two minutes and a calculator.

Step 1: work out your BMR

Your BMR (basal metabolic rate) is the energy your body uses just to keep you alive: breathing, pumping blood, staying warm. It is the biggest chunk of what you burn, and you burn it even lying in bed all day.

The most widely used formula is Mifflin-St Jeor. You need your weight in kilograms, your height in centimetres and your age in years.

• Men: BMR = (10 x weight) + (6.25 x height) - (5 x age) + 5
• Women: BMR = (10 x weight) + (6.25 x height) - (5 x age) - 161

Say you are a woman, 70kg, 165cm, 35 years old:

(10 x 70) + (6.25 x 165) - (5 x 35) - 161 = 700 + 1,031 - 175 - 161 = about 1,395 kcal.

That is your BMR. It is not your daily target. You move about during the day, so you burn more than this.

Step 2: work out your TDEE

Your TDEE (total daily energy expenditure) is your BMR plus everything else you do: walking, work, chores, the gym. You get it by multiplying your BMR by an activity factor.

Take our example woman with a BMR of 1,395. If she does light exercise a couple of times a week, her TDEE is about 1,395 x 1.375 = roughly 1,918 kcal. That is what she burns on an average day, so eating that amount keeps her weight steady.

Be honest with the multiplier. Most people who sit at a desk and go to the gym twice a week are closer to 1.375 than 1.55. Guessing high is the most common reason the maths stops working.

Step 3: set a sensible deficit

To lose weight you eat a bit less than your TDEE. The gap is called a deficit.

A deficit of about 500 kcal a day is the sweet spot for most people. It gives roughly 0.5kg of loss a week, it leaves you enough food to feel normal, and it is gentle enough to stick with for months.

For our example: 1,918 - 500 = about 1,418 kcal a day to lose weight at a steady pace.

If you want to go a touch faster you can push the deficit to 700 or so, but do not go daft. A very steep cut tends to backfire. You get ravenous, you slip, and you lose muscle along with fat.

The floor you should not go below

There is a lower limit. As a rough guide, most women should not eat below about 1,200 kcal a day and most men not below about 1,500, unless a doctor or dietitian is guiding them. Eat too little and you feel awful, your energy tanks, and the diet falls apart. Slower and steady beats fast and miserable every time.

Do the sums for you

Fettle (stayfettle.com) runs this exact maths for you. Pop in your details, pick your activity level, and it sets a daily calorie target with a sensible deficit already built in. Then you log your food against it, with UK foods and barcode scanning so a Tesco meal deal takes seconds. It is free and there is no account to set up.

A quick honest note

These numbers are estimates. The formulas are averages across lots of people, so your real burn might sit a little above or below. Weigh yourself over a couple of weeks and adjust: if the scale is not moving, trim 100 to 200 kcal; if you are losing faster than 1kg a week, eat a bit more.

This is general information, not medical advice. If you have a health condition, are pregnant, or want a plan built around your own needs, have a word with your GP or a registered dietitian first.