How Many Calories Should I Eat to Lose Weight?

Eat about 550 kcal a day below your maintenance calories for each 0.5 kg (1.1 lb) a week you want to lose, and don’t plan below 1,200 kcal if you’re a woman or 1,500 kcal if you’re a man. Those are the lower ends of the usual targets in the AHA/ACC/TOS guideline. Maintenance is the daily intake that holds your weight steady. If yours is 2,361 kcal, a 0.5 kg pace puts you at 1,811 kcal. Below, I work the sum for four example adults and show where the floor takes over.

How many calories should I eat to lose weight?

Take your maintenance number and subtract 1,100 kcal for every kg a week you want to lose. That 1,100 comes from the old 3,500 kcal-per-pound rule, which is about 7,700 kcal per kg, spread over seven days (7,700 ÷ 7). The rule has limits, and I test it in the next section.

Four steps give you a first target:

1. Estimate your maintenance calories.
2. Choose a pace: 0.25 kg a week is gentle, and 0.5 kg is the usual start.
3. Subtract the pace × 1,100 from maintenance.
4. Check that the pace is no more than 1% of your body weight a week, and use the floor if the target falls below it.

Maintenance comes from your age, height, weight and activity, and how many calories per day you need runs the sum for two adults. I used the adult equations in the 2023 NASEM energy report, which are fitted to measurements of real energy use. Then I took each adult down three ways, at 0.25, 0.5 and 0.75 kg a week. Targets are kcal a day.

Adult and maintenance	0.25 kg (0.55 lb) a week	0.5 kg (1.1 lb) a week	0.75 kg (1.65 lb) a week
Woman, 42 y, 168 cm, 80 kg, low active: 2,361	2,086	1,811	1,536
Man, 30 y, 180 cm, 95 kg, low active: 3,170	2,895	2,620	2,345
Woman, 58 y, 160 cm, 78 kg, inactive: 2,007	1,732	1,457	1,200 (floor), about 0.73 kg
Woman, 75 y, 150 cm, 66 kg, inactive: 1,690	1,415	1,200 (floor), about 0.45 kg	1,200 (floor), about 0.45 kg

The first row’s arithmetic: 575.77 − (7.01 × 42) + (6.60 × 168) + (12.14 × 80) = 2,361 kcal, then 2,361 − 550 = 1,811 kcal for the 0.5 kg pace.

Two things stand out. The same pace costs very different intakes: 0.5 kg a week is 1,811 kcal for the first woman and 2,620 kcal for the man. And the last woman can’t reach 0.5 kg without dropping under the floor. The slower pace follows from her numbers, not from anything she did.

Your own maintenance comes from your age, height, weight and activity, and the calorie calculator does that arithmetic with the NASEM 2023 equations. Its output stops at 1,200 calories for women and 1,500 for men, whatever pace you ask for.

Does the 3,500-calorie rule actually work?

I treat it as a rough guide for a few weeks. Over months it fails. In 2011 the Lancet paper by Hall and colleagues pointed out that official advice in the UK and US still treated it as exact. Their model followed a 100 kg sedentary man who cuts 480 kcal a day. The model had him reach a plateau near 75 kg. It took about a year to cover half of that loss and about three years to cover 95% of it. The 3,500-calorie rule predicted 22 kg lost in the first year, roughly double the model.

A lighter body burns less, so the same cut leaves a smaller gap as you shrink. Each kg you lose lowers your NASEM maintenance estimate by 11.71 to 12.56 kcal for women and 14.10 to 19.11 kcal for men. For the first woman in the table, losing 5 kg trims maintenance by about 61 kcal (5 × 12.14), so her 0.5 kg target moves from 1,811 to 1,750 kcal.

I use the 1,100 figure to set the first target and recompute after every 5 kg lost. TDEE for weight loss starts the same subtraction from total daily energy expenditure. I don’t trust the rule to predict a date. Expect the scale to slow as you lose, because the same intake leaves a smaller gap in a lighter body.

How fast is too fast, and how low is too low?

The NHS says to aim for 1 to 2 lb, or 0.5 to 1 kg, a week. The CDC gives the same 1 to 2 pounds a week. I stop at 0.75 kg in the table, so no faster column exists.

On energy, the 2013 AHA/ACC/TOS guideline describes a deficit of 500 or 750 kcal a day. Its usual intake targets are 1,200 to 1,500 kcal for women and 1,500 to 1,800 kcal for men. I treat the lower end of each range as a floor. In kilojoules, which Australian labels use, the floors are 5,021 kJ and 6,276 kJ.

A second limit is relative to your size. A review of contest preparation for natural bodybuilders suggests that losing about 0.5 to 1% of body weight a week may protect lean mass better than losing faster. The context is narrow, but I borrow 1% as my ceiling. For a 66 kg adult that is 0.66 kg. It is why the 0.75 kg column is off the table for the last woman even before her floor applies.

When both limits bite, the floor wins and the pace shrinks. The woman at 1,690 kcal maintenance gets 1,200 kcal and a pace of about 0.45 kg, because (1,690 − 1,200) ÷ 1,100 = 0.45. Take the smaller pace and leave the floor where it is.

What does a 550-calorie cut look like in food?

It is a small amount of oil or nuts and a very large amount of vegetables. I divided 550 kcal by the energy in a gram of several foods, using USDA FoodData Central records. Each row is 550 ÷ the record’s kcal per gram.

Food (state)	Energy per 100 g	Grams that equal 550 kcal
Olive oil	884 kcal	62 g (about 4.6 tablespoons)
Peanut butter, creamy	589 kcal	93 g
Almonds, raw	584 kcal	94 g
Rolled oats, dry	379 kcal	145 g
Chicken breast, braised	166 kcal	331 g
White rice, cooked	130 kcal	423 g (2.7 cups)
Banana	88 kcal	625 g (5.4 bananas)
Broccoli, raw	32 kcal	1,719 g

The record for olive oil lists 884 kcal and 13.5 g to the tablespoon, so 62 g is about 4.6 tablespoons. Bananas use the record’s 115 g portion, and cooked rice its 158 g cup. Where a record gives two energy values, I used the specific Atwater figure.

Look at the top of the table. Oil and nuts reach 550 kcal in under a hundred grams, so measuring them is the cheapest way to find 100 or 200 kcal. Weigh the spoonful of oil for a week. Every extra 5 g that slips into the pan is 44 kcal (5 × 8.84). I trim dense items first. Vegetables stay.

How do I know the target is working?

Log your food and weigh yourself for two weeks, then compare. Weigh on 3 mornings a week and average each week, because single readings jump around. By the rule above, a 0.5 kg pace should show up as about 1 kg over two weeks. If it’s on track, keep going.

When nothing moves, don’t cut again yet. Check the log first. One tablespoon of olive oil that never reached the log is 119 kcal (13.5 g × 8.84). My rule is to change the target in steps of 100 to 200 kcal and then wait two more weeks. It’s mine, not a published one. Burning more instead of eating less is a separate question: how many calories should I burn a day.

Who should not follow this?

This article is for adults who have a reason to lose weight. For the opposite goal, see how many calories over maintenance to gain a pound. If your BMI is already in the usual range of 18.5 to less than 25, ask your doctor before you aim to lose more. The same goes if you are pregnant or breastfeeding, under 18, or managing a health condition or a medicine that changes your weight. The equations don’t cover those cases, and a calculator shouldn’t set targets for them.

If counting calories has started to feel hard to stop, or eating feels out of control, talk to someone: ANAD in the US (1-888-375-7767), Beat in England (0808 801 0677), NEDIC in Canada (1-866-633-4220) or the Butterfly Foundation in Australia (1800 33 4673). If you’re in danger right now, call your local emergency number. Other UK numbers and crisis lines are on our crisis support page.