How many calories should I eat to lose weight? Work it out in 4 steps

Why there's no one-size-fits-all number

How many calories you should eat to lose weight depends on how many you burn. A common rule of thumb is about 2,000 kcal a day for an average woman and 2,500 for an average man, but the real figure changes with your age, weight, height and how much you move¹.

That's why the fixed numbers you see online (1,200, 1,500, 1,800) work for some people and not for others. A more useful approach: estimate your own needs, subtract a moderate amount, then watch how your body responds.

How to work out your calories in 4 steps

1Estimate your resting metabolism

Your resting metabolism is the energy your body uses just to keep running, before any movement. One of the most widely used formulas is Mifflin-St Jeor²:

• men: 10 × weight (kg) + 6.25 × height (cm) − 5 × age + 5
• women: 10 × weight (kg) + 6.25 × height (cm) − 5 × age − 161

Using pounds and inches? Multiply pounds by 0.454 to get kilograms and inches by 2.54 to get centimeters. It's an estimate: two people with the same stats can burn slightly different amounts. That's fine, because step 4 is there to correct it.

2Multiply by your activity level

Next, add the movement in your day by multiplying by a physical activity level (PAL). Typical values range from 1.4 for sedentary people to 2.5 for very active people; 1.6 describes someone who mostly sits at work and does moderate exercise at least once a week³.

Activity level (approximate)	Example	Multiplier
Sedentary	Desk job, little movement	1.4
Lightly active	Desk job, a walk or workout once a week	1.6
Active	On your feet at work or moving most days	1.8
Very active	Physical job or intense exercise every day	2.0–2.5

The result is your maintenance calories: the amount at which your weight stays roughly stable.

Try this: if you're between two levels, start with the lower one. Step 4 will tell you if you need to move it up.

3Subtract a moderate deficit

To lose weight, you need to eat a bit less than you burn. Weight-management programs usually aim for a deficit of 500–750 kcal a day⁴. A pace of 1–2 lb (0.5–1 kg) a week is the recommended rate for steady weight loss⁵.

In professionally supervised programs for people with overweight, the target often ends up around 1,200–1,500 kcal for women and 1,500–1,800 for men, always adjusted for each person's weight and activity⁴. These are reference values, not a floor to aim for: diets under 800 kcal should only be followed under medical supervision⁵.

4Track your weight and adjust

The number you worked out is a starting point. Weigh yourself at the same time of day a few times a week and look at the trend over 2–4 weeks, not a single day:

• losing about 1–2 lb (0.5–1 kg) a week: keep going;
• weight hasn't moved for 3–4 weeks: trim your portions a little or add some movement;
• losing more than 2 lb (1 kg) a week for many weeks: you're probably eating too little, so add something back.

Two worked examples

Here's how it works with real numbers. Results are rounded.

	Person A	Person B
Stats	Woman, 35, 5'5" (165 cm), 154 lb (70 kg)	Man, 40, 5'11" (180 cm), 187 lb (85 kg)
Resting metabolism	about 1,400 kcal	about 1,780 kcal
Activity level	1.6 (desk job, walks)	1.6 (desk job, weekly soccer)
Maintenance calories	about 2,230 kcal	about 2,850 kcal
With a 500 kcal deficit	about 1,730 kcal	about 2,350 kcal

As you can see, the result is nowhere near the classic 1,200 kcal: for many people, eating that little would mean too big a cut to keep up.

Why weight loss slows down after a few weeks

A popular rule says a 3,500-calorie deficit equals one pound of weight lost. It's a static calculation: it ignores the fact that your body adapts. As your weight drops, so do your resting metabolism and the energy you spend moving⁶.

In practice, your starting deficit shrinks on its own over the weeks, and weight loss slows down. It doesn't mean you did anything wrong:

• recalculate your needs every time you've lost a few pounds, using your new weight;
• keep moving, or move a bit more, to help make up the difference;
• don't chase bigger and bigger cuts: a small adjustment works better.

It's not just how many calories, but which ones

Calorie for calorie, some meals keep you full much longer than others. To make a deficit work without feeling hungry all the time:

• protein at every meal: it keeps you full longer and helps you hold on to muscle while you lose weight⁷. Beans, lentils, yogurt, eggs, tofu and dairy are easy options;
• vegetables and whole grains: they fill your plate with fewer calories;
• watch liquid calories: soda, juice and alcohol add up fast and don't fill you up.

Here's what a day with a moderate deficit might look like: oatmeal and fruit for breakfast, whole wheat pasta with chickpeas for lunch, yogurt and fruit as a snack, tofu with vegetables and potatoes for dinner. It's not a menu to copy: portion sizes depend on your own needs. For more practical ideas, read our guide on how to lose weight without dieting.

How to know how many calories you actually eat

Working out your needs is half the job: the other half is knowing how much you eat today. Research consistently links tracking your meals with weight loss⁸. You don't need to weigh everything: even an estimate, done consistently, shows you where the calories go.

With eatamame you set your goal and get a personalized plan with an estimated date for reaching it. Then just snap a photo or describe your meal, even by voice, to see estimated calories and macros. If you want tips on photographing your plates, check out the guide on how to count calories from a photo.

The most common mistakes

• Copying someone else's number: a friend's or coworker's needs can be very different from yours.
• Cutting too much: a bigger deficit is harder to stick with, and very low-calorie diets (under 800 kcal) are only for medical supervision⁵.
• Counting exercise twice: if it's already in your activity level, don't add it on top of your daily calories.
• Forgetting dressings, drinks and bites: these are the calories that slip through most often.
• Judging after a few days: your weight goes up and down with water and salt. What counts is the trend over a few weeks.