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How to lose or gain weight using BMR & TDEE

Updated: Jul 11

Science Behind Weight Loss

To understand this, we first need to understand 2 concepts
1. BMR

Basal metabolic rate ( BMR ) evaluates the minimum number of calories an individual requires to run their basic life functions such as circulation, breathing, digestion and absorption of nutrients during a 24 hour period of rest.

If an individual is trying to lose weight, calculating their BMR can help in establishing how many calories individual exactly need to consume each day.

How to calculate your BMR?

There are different ways and equations to calculate BMR, like Mifflin-St Jeor or Harris- Benedict. Below details show you how to exactly calculate the BMR using different equation. There's also an easier way by using Smart Scale as below.

Mifflin-St Jeor Equation according to National Library Of Medicine. Analysis of Predictive Equations for Estimating Resting Energy Expenditure in a Large Cohort of Morbidly Obese Patients - PMC (nih.gov)

9.99*weight (Kg) + 6.25*height (cm) − 4.92*age + 166*sex (M = 1; F = 0) −161

Harris- Benedict Formula according to National Library Of Medicine. Analysis of Predictive Equations for Estimating Resting Energy Expenditure in a Large Cohort of Morbidly Obese Patients - PMC (nih.gov)


88.362 + 4.799*height (cm) + 13.397*weight (kg) − 5.677*age


447.593 + 3.098*height (cm) +9.247*weight (kg) − 4.330*age

According to research, the Mifflin-St.Jeor equation is useful way. However, there are variations in accuracy levels such as it is low in precision for obese people and more precise for non obese population.

To avoid the hassles of using the equations, just use body composition scale and Lifetrons Health app which eliminates all the guesswork and gets accurate readings.

What is TDEE and how to calculate TDEE?

Total Daily Energy Expenditure (TDEE) is defined as an estimation of the number of calories you burn every day which includes physical activity. It is calculated by multiplying your Basal Metabolic Rate (BMR) by 1.2 to 1.9 on the basis of your activity level. It is essential to calculate TDEE to understand how many calories one needs to consume to maintain, gain or lose weight.

Sedentary ( minimum exercise or no exercise)

TDEE= BMR × 1.2

Light ( light exercise for 1 to 2 days )

TDEE= BMR × 1.37

Moderate ( exercise for 3 to 5 days )

TDEE= BMR × 1.55

Heavy ( exercise for 6 to 7 days )

TDEE= BMR × 1.72

How to use BMR & TDEE to Lose or Gain Weight

We will take a weight loss example, but similar logic is applied for weight gain. To lose weight, it is necessary to consume less calories than you required. That's called a "Calorie Deficit". If you consume more calories than you burn, then you don't have a calorie deficit and wont be able to lose weight. For example, if your requirement is of 2000 calories (BMR) but only consume 1800 calories. This means you have a deficit of 200 calories. Research suggest '" Low Calorie Diet - an overview | ScienceDirect Topics" that a calorie deficit of 500 calories a day is sufficient for weight loss. However, this changes are based on individuals.

When there's a calorie deficit i.e. 200 Calories less than required in above example, your body gets those 200 calories (energy) from the stored reserve (Fat). That's a FAT Burn. Your body can use it to keep moving instead of using energy from food. This helps you to loose weight scientifically. In general, individual should loose FAT and not weight. Weight can be reduced by lower hydration, loosing muscle and so on, which is not healthy way to loose weight. You can accurately track these using Lifetrons Smart Scale.


If your goal is to gain weight, you need to consume more than your TDEE and if it is to lose weight, you have to consume less than your TDEE.

Health apps such as Lifetrons can help evaluate your actual or desirable energy needs by putting in your basic information and nutrition goals.

Disclaimer: Blog is generated for informative purposes. Views expressed in the blog are personal and belong to the author of the blog. Lifetrons is just publishing it on behalf of the author.

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