How Many Calories Should I Eat to Lose Weight?

To lose weight you need to eat fewer calories than your body burns. That part is simple. The useful question is how many fewer, and that depends on one number most people never calculate: their maintenance calories.

The short answer: find your maintenance calories, then eat about 500 kcal a day less. For most people that means losing roughly 0.5 kg (1 lb) a week at the start. Our calorie calculator does the maths for you in a few seconds.

Step 1: find your maintenance calories

Maintenance calories, also called TDEE (total daily energy expenditure), are the calories that keep your weight stable. They come from two parts:

• Resting metabolism (BMR): the energy your body uses to breathe, pump blood and keep you warm. For most adults it’s 60 to 70% of the total.
• Everything else: walking, working, training and even digesting food.

The most reliable formula for healthy adults is the Mifflin-St Jeor equation:

• Women: 10 × weight in kg + 6.25 × height in cm − 5 × age − 161
• Men: 10 × weight in kg + 6.25 × height in cm − 5 × age + 5

Then multiply the result by your activity level:

Activity level	What it looks like	Multiplier
Sedentary	Desk job, little exercise	1.2
Lightly active	Exercise 1 to 3 days a week	1.375
Moderately active	Exercise 3 to 5 days a week	1.55
Very active	Exercise 6 to 7 days a week	1.725
Extremely active	Physical job or hard daily training	1.9

Step 2: choose your deficit

Once you know your maintenance, pick a deficit you can actually live with:

Daily deficit	Expected pace at the start	Best for
250 kcal	About 0.25 kg (0.5 lb) a week	Small amounts to lose, busy lives
500 kcal	About 0.5 kg (1 lb) a week	Most people
750 kcal	About 0.75 kg (1.5 lb) a week	Larger bodies, short periods

The NHS weight loss plan works on the same idea: a deficit of around 500 to 600 kcal a day for a steady loss of about 0.5 kg a week.

Bigger deficits look faster on paper, but they make you hungrier, cost more muscle and are much harder to keep up for months. The best deficit is the one you can still follow in week ten.

A floor to respect: most women shouldn’t go below 1,200 kcal a day and most men below 1,500 kcal without medical supervision. If your maths lands under those numbers, move more instead of eating less. Not sure how big your deficit should be? Read what a calorie deficit is and the signs it’s too big.

A worked example

Sara is 32, 168 cm tall, weighs 72 kg and goes to the gym twice a week.

1. BMR: 10 × 72 + 6.25 × 168 − 5 × 32 − 161 = 1,449 kcal
2. Maintenance: 1,449 × 1.375 = about 1,990 kcal
3. Target with a 500 kcal deficit: about 1,490 kcal a day

At that target Sara can expect to lose around 0.5 kg a week for the first couple of months, then a little less.

Why weight loss slows down

The old rule says that 3,500 kcal equals one pound of fat (7,700 kcal per kg), so a 500 kcal deficit should mean one pound a week forever. Real bodies don’t work like that.

As you lose weight, a smaller body burns less energy, so the same intake becomes a smaller deficit. Research by Kevin Hall and colleagues at the US National Institutes of Health showed that the classic rule overestimates long-term weight loss for this reason. In practice:

• The first week or two often show a bigger drop, mostly water and stored carbohydrate.
• Months one to three follow the expected pace quite closely.
• After that progress slows, which is normal and not a sign that something is wrong.

When your weight has been flat for three or four weeks, recalculate your maintenance with your new weight, or add 20 to 30 minutes of walking a day.

The number is only as good as your tracking

Most failed diets don’t fail on the maths. They fail because people eat more than they think. In a well-known study published in the New England Journal of Medicine, people who said they couldn’t lose weight on low intakes were actually underreporting what they ate by about 47%.

Keeping a food diary helps a lot. A systematic review of weight loss studies found that people who consistently record what they eat lose more weight than those who don’t. The records don’t need to be perfect, they need to be consistent. The few things worth watching:

• Cooking oil and dressings. A tablespoon of olive oil is about 120 kcal and rarely makes it into the diary.
• Drinks. Juice, lattes, beer and wine add up quickly.
• Weekends. Two relaxed days can cancel five careful ones.
• Portions by eye. Weigh your usual foods a few times so your eye learns what 100 g of pasta looks like.

This is exactly the friction BananaCal was built to remove: take a photo of your plate and it estimates the calories and macros, so logging takes seconds instead of minutes. Curious how close those estimates are? Read are AI calorie counting apps accurate.

Don’t forget protein

Where your calories come from matters too. When you eat less, getting enough protein helps you keep your muscle and feel full on fewer calories. A meta-analysis of weight loss trials found that higher-protein diets during a calorie deficit led to slightly more fat loss and better preservation of lean mass.

A practical target is 1.2 to 1.6 g of protein per kg of body weight a day. Read more in our guide on how much protein you need per day.

Quick checklist

• Calculate your maintenance calories with the calorie calculator.
• Subtract 250 to 500 kcal, and stay above 1,200 (women) or 1,500 (men).
• Aim for 1.2 to 1.6 g of protein per kg of body weight.
• Track everything for at least two weeks, including oil and drinks.
• Judge progress on weekly averages, not daily weigh-ins.
• Recalculate after every 4 to 5 kg lost.