Should I eat my BMR to lose weight?

Usually no. BMR is only what your body burns at complete rest, so eating at BMR is often a 25 to 40% deficit for an active person. Eat around your TDEE minus a modest 10 to 25% instead, and stay above your BMR unless a doctor or dietitian is supervising you.

Is TDEE the same as maintenance calories?

Yes. TDEE (total daily energy expenditure) is the number of calories you burn in a full day, including activity, so eating at your TDEE keeps your weight roughly steady. That's why people use the two terms interchangeably.

Which BMR formula is the most accurate?

For most healthy adults, Mifflin-St Jeor. A 2005 systematic review found it predicted resting metabolic rate within 10% of measured values in more people than the other common equations. If you know your body fat percentage reasonably well, Katch-McArdle (370 + 21.6 × lean mass in kg) is a good alternative, especially for very muscular people.

Does BMR go down as you lose weight?

Yes. A lighter body burns less at rest, so both BMR and TDEE fall as you lose weight. On top of that, the body adapts during dieting and may burn somewhat less than the formula predicts, so recalculate every 4 to 5 kg lost.

BMR vs TDEE: What Each Number Means and Which One to Eat To

BMR (basal metabolic rate) is what your body burns at complete rest just to stay alive. TDEE (total daily energy expenditure) is BMR plus everything you do in a day, from walking to the gym session, so it's always the bigger number. For weight loss, eat to your TDEE minus a modest 10 to 25%, not to your BMR, and don't go below your BMR long-term without a doctor or dietitian involved.

You can get both numbers in a minute with the BMR calculator. The rest of this post explains what the numbers mean, how much to trust them, and how to find your real TDEE.

What is BMR?

BMR is the energy your body uses lying still, awake, hours after your last meal. It keeps your heart, lungs and brain running. It's roughly what you'd burn staying in bed all day.

You'll also see RMR (resting metabolic rate). It's measured under slightly looser conditions, but calculators treat the two as the same.

The main things that decide your BMR:

Body size. Heavier and taller people burn more.
Lean mass. Muscle and organs burn more than fat. This is why men usually have a higher BMR than women of the same weight.
Age. BMR tends to drift down with age (the formula below takes off 5 kcal for every year), partly because people tend to lose muscle.

What is TDEE?

TDEE is your full day's burn: BMR, plus the energy used to digest food, plus exercise, plus all the everyday movement like walking to the bus stop, climbing stairs and cooking. That last part varies a lot. A shopkeeper on their feet all day and an office worker who drives everywhere can have very different TDEEs with the same BMR and gym routine.

TDEE is the same thing as maintenance calories. Eat at it and your weight stays roughly steady. Eat below it and you lose; above it and you gain.

How do you calculate BMR? The Mifflin-St Jeor equation

The most widely used formula is the Mifflin-St Jeor equation, published in the American Journal of Clinical Nutrition in 1990. It was built from measurements on 498 healthy adults aged 19 to 78, both normal weight and obese.

Men: BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age (years) + 5
Women: BMR = 10 × weight (kg) + 6.25 × height (cm) − 5 × age (years) − 161

A worked Indian example

Two hypothetical people:

Rahul, 30, 175 cm, 78 kg:

10 × 78 = 780
6.25 × 175 = 1,093.75
5 × 30 = 150
BMR = 780 + 1,093.75 − 150 + 5 = about 1,729 kcal

Priya, 26, 158 cm, 62 kg:

10 × 62 = 620
6.25 × 158 = 987.5
5 × 26 = 130
BMR = 620 + 987.5 − 130 − 161 = about 1,317 kcal

How does BMR turn into TDEE?

You multiply BMR by an activity factor. These five multipliers are a widely used convention, and the same ones the calorie calculator uses:

Activity level	Multiplier	Looks like	Rahul's TDEE	Priya's TDEE
Sedentary	1.2	Desk job, little or no exercise	about 2,075	about 1,580
Lightly active	1.375	Light exercise or walks 1 to 3 days a week	about 2,377	about 1,810
Moderately active	1.55	Gym or sport 3 to 5 days a week	about 2,680	about 2,041
Very active	1.725	Hard training 6 to 7 days a week	about 2,982	about 2,271
Athlete	1.9	Training twice a day, or physical job plus training	about 3,285	about 2,501

Notice how big the gap is. Rahul's TDEE at the moderately active level is about 950 kcal above his BMR. That gap is the whole reason eating "to your BMR" is a bad plan.

Be honest here. An hour in the gym four days a week doesn't make you "very active" if you sit for the other 23 hours. If you're torn between two levels, pick the lower one.

Which number should you eat to?

Eat to your TDEE, adjusted for your goal.

To lose fat: TDEE minus 10 to 25%. ICMR-NIN's Dietary Guidelines for Indians 2024 describe a 500 to 750 kcal daily deficit as typical for weight loss and advise not going beyond a 40% deficit, because protein's ability to protect muscle breaks down past that point.
To maintain: eat around TDEE.
To gain muscle: a small surplus above TDEE, plus progressive training. The weight gain diet for skinny people covers this with Indian food.

For our examples:

	Rahul (moderately active)	Priya (lightly active)
BMR	about 1,729	about 1,317
TDEE	about 2,680	about 1,810
15% deficit	about 2,278	about 1,539
20% deficit	about 2,144	about 1,448
25% deficit	about 2,010	about 1,358

Every one of those targets stays above their BMR. That's the point.

Why not eat at or below BMR?

There's no magic line at BMR, but it's a sensible floor for unsupervised dieting. If Rahul ate 1,700 kcal, that's a deficit of about 37%, close to ICMR-NIN's 40% limit. Deficits that big make it harder to keep muscle, train well and stick with it.

Also keep to the usual minimums: about 1,200 kcal a day for women and 1,500 for men unless you're under medical supervision. If you have diabetes on medication, kidney disease, are pregnant or breastfeeding, are under 18, or have a history of an eating disorder, see a doctor before you cut calories at all.

For more on choosing the size of your deficit, see calorie deficit and maintenance calories.

How accurate are these estimates?

Reasonably good for groups of people, less reliable for any one person.

A 2005 systematic review by Frankenfield and colleagues compared the four most common equations (Harris-Benedict, Mifflin-St Jeor, Owen and WHO/FAO/UNU). Mifflin-St Jeor was the most reliable: it predicted resting metabolic rate within 10% of the measured value in more people than any other, with the narrowest error range.

The review also found "noteworthy errors" for individuals, and noted that older adults and ethnic minorities were underrepresented in building and testing these equations. Indians weren't the focus of that research, so treat your number as a starting estimate.

Then the activity multiplier adds a rough guess on top of a rough guess. A 10% BMR error plus a slightly optimistic activity level can put your TDEE off by a few hundred kcal. That's why the real test below matters more than the formula.

What is Katch-McArdle, and when should you use it?

Mifflin-St Jeor assumes average body composition, so it can miss for someone very muscular or carrying a lot of fat. If you know your body fat percentage, the Katch-McArdle formula works from lean mass instead:

BMR = 370 + 21.6 × lean body mass (kg)

This equation actually comes from J.J. Cunningham's 1991 review in the American Journal of Clinical Nutrition, which found fat-free mass explained 65 to 90% of the variation in resting energy expenditure across studies. It has no age or sex term, because lean mass already accounts for most of those differences.

Here's Rahul again at 78 kg:

Rahul's body fat	Lean mass	Katch-McArdle BMR	Mifflin-St Jeor BMR
22%	about 60.8 kg	about 1,684	about 1,729
12%	about 68.6 kg	about 1,853	about 1,729

At 12% body fat, a lean lifter, the Mifflin number is about 120 kcal too low. Use Katch-McArdle only if your body fat estimate is decent. A tape-measure estimate from the body fat calculator is fine. A cheap bathroom-scale reading often isn't.

Why does your TDEE drift as you lose weight?

Two reasons.

1. You're lighter. If Rahul drops from 78 to 70 kg, his Mifflin BMR falls by 80 kcal, and his moderately active TDEE falls from about 2,680 to about 2,556. The same diet now gives a smaller deficit. That's partly why Kevin Hall's 2011 Lancet modelling paper found body weight responds to a lasting change in intake slowly, with a half-time of about a year.

2. Your body adapts. During dieting, energy use falls a bit more than weight loss alone predicts. This is adaptive thermogenesis. Rosenbaum and Leibel's 2010 review describes how metabolic, hormonal and behavioural responses, many linked to the hormone leptin, push back against a reduced body weight.

How big is it? In a 2024 study of 44 adults with severe obesity who lost about 18 kg in 10 weeks, resting energy use was about 121 kcal a day lower than predicted. The authors expected the effect to be small or absent once weight stabilised. So it's real, but it doesn't stop fat loss while you're genuinely in a deficit.

The fix is boring: recalculate every 4 to 5 kg and check against the scale.

How do you find your real TDEE?

The formula gives you a starting point. Your weight trend gives you the answer.

Eat a consistent amount for 2 to 3 weeks and log it honestly, including oil, chai sugar and weekend meals. The Indian food calorie counter or the Indian food calorie chart helps here.
Weigh yourself at least 4 mornings a week, after the toilet and before food.
Average your week 1 weigh-ins and your week 3 weigh-ins.
Work out the change.

A hypothetical example: Rahul eats an average of 2,200 kcal a day. His week 1 average is 78.0 kg and his week 3 average, 14 days later, is 77.4 kg.

Loss: 0.6 kg
Rough energy in that loss: 0.6 × 7,700 = 4,620 kcal
Per day: 4,620 ÷ 14 = 330 kcal
Real TDEE: 2,200 + 330 = about 2,530 kcal

That's below his formula estimate of 2,680, so his activity level was probably a bit generous. The 7,700 kcal per kg figure is a rough rule and early weeks include water changes, so this is still an estimate. But it's based on your body, not an average.

If your weight held steady, your intake is your TDEE. If it went up, your TDEE is below what you ate.

If your target lands around 1,500 kcal, the 1,500 calorie Indian diet plan shows what a full day looks like.

The short version

BMR is your burn at rest; TDEE is your full day's burn, and the one you plan meals around
Calculate BMR with Mifflin-St Jeor, or Katch-McArdle if you know your body fat well
Multiply by an honest activity factor (1.2 to 1.9) to get TDEE
For fat loss, eat TDEE minus 10 to 25%, and stay above your BMR without supervision
Expect the formula to be off by a few hundred kcal; check it with 2 to 3 weeks of weigh-ins
Recalculate every 4 to 5 kg lost

This is general information, not medical advice.

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Cover photo: Flatlay Food by Brooke Lark, CC0, via stocksnap.