How to calculate calorie deficit?

A calorie deficit is the key when you want to target fat loss or lose weight. The two key elements to calculate your goal calorie deficit is by estimating the calories you are consuming in your food and beverages and factoring in what you burn through activity. 

What is a Calorie Deficit? 

A calorie deficit is when you are burning more calories than you are consuming over time. For example, if you consume 2000 calories a day but burn only 2500 calories, you’ll be in a 500 calorie deficit. There are two ways based on which you can achieve a deficit in and i.e. – your diet and exercise. Eating less or doing more exercise or frequently a combination of both.

How to Calculate a Calorie Deficit?

You can calculate it easily in 3 steps ~

1. Calculation of daily maintenance calorie intake

Firstly, calculate your basal metabolic rate, or BMR. There are several options to do so but the Mifflin St. Jeor equation is commonly researched and regarded as a good estimate.

Men: BMR = 10 x weight (kg) + 6.25 x height (cm) – 5 x age (years) + 5

Women: BMR = 10 x weight (kg) + 6.25 x height (cm) – 5 x age (years) – 161

This BMR is the number of calories your body burns if you did nothing but lay in bed all day. 

Next step is to multiply the BMR you calculated above by an activity factor in the table given below. 

Physical Activity Level	Physical Activity Ratio	Description
Sedentary	1.55	Doing no structured exercise  & sitting most of the day
Moderately active	1.85	Low active or Sedentary job with 1 hour exercise daily  No structured exercise but Active job (moderate movement 8+ hrs per day)
Vigorously active	2.2	1 hour exercise per day & Active job (moderate movement 8+ hours per day)  2 hours of exercise daily but low active or sedentary job
Extremely active	2.4	Training more than 2 hours daily  At least 1 hr of exercise daily + moderately active job (walking all day)

 If you are between two levels, choose a number in the middle.
Maintenance Calories = Multiply your BMR x Activity Factor

2. Adjustment in calorie intake for weight loss

We can calculate the calorie intake level needed for weight loss once we know our maintenance calories. For example let’s say 2500 is your maintenance calories. Now, 7,700 calories is about 1 kilo of body fat & our aim is 0.5-1 kilo of weight loss per week. Therefore:

 500 calorie deficit per day = 3,500 calorie deficit per week

700 calorie deficit per day = 4,900 calorie deficit per week

To have these calorie deficits, combination of eating less and burning more is more needed. You might have to exercise a little bit harder if you have a strictly healthy diet and aren’t sure where to cut calories. It’s crucial to keep track of the calories you eat by measuring and weighing your portions.

3. Adjust for physical activity

For weight loss, your daily net calories must be about 500 calories lower than your BMR. 

Net Calories = Food Calories – Exercise Calories

Calculating exact calories your burn during exercise is tricky and not always straight forward as it is not an exact science. Your habits – both in the kitchen and gym are to be kept in mind in order to make sustainable changes & have long term success for fat loss.

Also, rather than these equations and calculating BMR manually, you can use a device that measures your heart rate and adjusts for your age, weight, and activity level or refer to a calorie burn chart to estimate your exercise calories.