Your BMR Explained: How Many Calories Do You Actually Burn at Rest?

Your BMR, or Basal Metabolic Rate, is the number of calories your body burns at complete rest to keep you alive. No movement. No digestion. No thinking. Just the fundamental work of staying alive: breathing, circulating blood, maintaining body temperature, replacing cells.

For most Indian adults, BMR is between 1,200 and 1,800 calories per day. This is the absolute floor of your calorie needs, before any physical activity is added.

Understanding your BMR matters because it is the foundation of every calorie calculation that follows: total daily expenditure, weight loss deficits, weight gain surpluses. Get the floor wrong and every calculation above it is wrong too.

Short answer: what BMR is used for

1. The baseline to calculate TDEE (total daily energy expenditure)
2. The floor below which you should rarely eat for extended periods
3. A rough indicator of metabolic health

How BMR is calculated

The most accurate formula for most adults is the Mifflin-St Jeor equation, which uses your weight, height, age, and sex.

For men: BMR = (10 x weight in kg) + (6.25 x height in cm) minus (5 x age) + 5

For women: BMR = (10 x weight in kg) + (6.25 x height in cm) minus (5 x age) minus 161

For a 35-year-old woman, 60kg, 165cm: BMR = (10 x 60) + (6.25 x 165) minus (5 x 35) minus 161 = 600 + 1031 minus 175 minus 161 = 1,295 calories

This is her daily calorie need at complete rest, before any activity.

Older formulas (and why Mifflin-St Jeor is the standard)

The Harris-Benedict equation (1919, revised 1984) was the earlier standard. Most Indian health apps still use it. It tends to over-estimate BMR by 5 to 10 percent for modern adults because it was calibrated on a more active population.

The Katch-McArdle formula uses lean body mass, which is more accurate but requires a body composition measurement you typically do not have.

For most Indian adults, Mifflin-St Jeor is the best balance of accuracy and simplicity.

What affects your BMR

Factors you cannot easily change

• Age. BMR drops about 2 percent per decade after age 30 as muscle mass naturally declines.
• Height. Taller bodies have more surface area to maintain.
• Sex. Men have 5 to 10 percent higher BMR than women at the same weight due to more muscle mass.
• Genetics. Up to 20 percent variation in BMR at the same body size.

Factors you can change

• Muscle mass. Each kg of muscle burns roughly 13 calories per day. Adding 5kg of muscle raises daily BMR by around 65 calories.
• Thyroid function. Underactive thyroid lowers BMR by 10 to 30 percent. If your energy is chronically low, check thyroid first.
• Sleep quality. Consistent poor sleep lowers BMR by 5 to 10 percent over time.
• Chronic dieting. Long-term eating below BMR causes adaptive thermogenesis, reducing BMR by 10 to 20 percent. This is the main mechanism behind "I eat nothing and still don't lose weight."

The big mistake: eating below BMR

Many weight loss plans recommend 1,200 to 1,400 calories per day for women. For a woman whose BMR is 1,300, this is at or below her BMR. Eating at BMR for weeks or months leads to:

1. Metabolic slowdown (BMR drops further as body conserves energy)
2. Muscle loss (body breaks down muscle for fuel)
3. Hormonal disruption (thyroid and sex hormones dysregulate)
4. Rebound weight gain (as soon as eating normalises)

Weight loss that sticks typically happens at TDEE minus 300 to 500 calories, not at BMR or below. Your BMR should be the floor, not the target.

What your BMR tells you about your metabolic health

BMR slightly higher than predicted: usually good. More muscle mass or higher activity history.

BMR slightly lower than predicted: often due to chronic dieting, low muscle mass, or undertreated thyroid.

BMR significantly lower than predicted (by more than 10 percent): worth investigating. Common causes: undiagnosed hypothyroidism, long-term very-low-calorie diets, post-pregnancy metabolic slowdown (see our postpartum nutrition guide).

How to keep your BMR healthy

Four levers, in order of impact:

1. Maintain muscle mass. Resistance training twice a week is the most effective BMR-preservation strategy at any age.
2. Eat enough protein. 1.2 to 1.6g per kg of body weight daily. Protein itself has the highest thermic effect of any macronutrient (20 to 30 percent of protein calories are burned just digesting it).
3. Do not chronically diet. Repeated aggressive cuts lower BMR. Plan weight loss with reverse-dieting breaks.
4. Sleep 7 to 8 hours. Consistent poor sleep measurably reduces BMR.

BMR during weight loss

As you lose weight, your BMR drops for two reasons:

1. Mathematical: you weigh less, so the formula gives a lower number.
2. Adaptive: the body actively reduces BMR below the predicted formula number to conserve energy.

For every 10 kg lost, BMR typically drops 80 to 120 calories per day. This is why weight loss plateaus as you get smaller.

Plan for this: recalculate BMR every 2 to 4 kg of weight loss. Adjust your calorie target accordingly.

The bottom line

BMR is the floor of your calorie needs, not the target. Most Indian adults burn 1,200 to 1,800 calories just to exist. Eating at or below this number for extended periods backfires.

Calculate your BMR here, then use the result to build a realistic TDEE and calorie target. For a plan built around your actual metabolism, learn how DietOwl works.