How many calories should you eat to lose weight? Well, it depends on how much your Total Daily Energy Expenditure (TDEE) is.
Your TDEE is the number of calories you burn each day to maintain your body. If you want to lose weight, you should eat fewer calories than your TDEE.
But, how do you know your TDEE? Well, before we discuss how to calculate your TDEE, let’s first explore what calories are and how they relate to weight loss.
What Are Calories?
What exactly are calories? A calorie is a unit of heat energy. In fat loss, calories are very important because your fat is a storage container for energy reserves from food.
The unit used to measure food energy is actually the kilocalorie or Calorie (with an uppercase C). One kilocalorie is the amount of heat required to raise the temperature of 1 kg of water by 1 degree Celsius. One kilocalorie is equal to 1000 calories (with a lowercase c).
In scientific literature, the distinction between kilocalorie or Calorie (with an uppercase C) and calorie (with a lowercase C) is done strictly. However, in popular literature, the term “calorie” (with a lowercase c) is commonly used to refer to what is actually a kilocalorie. This article follows the convention of popular literature.
Now, your body burns calories every day for your essential bodily functions and activities―this is what we referred to above as your TDEE. Similarly, your body gets calories every day from the food you eat.
If the calories you burn are greater than the calories you eat, your body will burn the energy reserves that are stored as fat to make up for the calorie deficit. If the calories you eat are greater than the calories you burn, your body will store the excess energy as fat.
So, if you want to lose weight, you should eat fewer calories than you burn. You can of course increase your calorie expenditure by exercising. And we do recommend you to exercise. However, it’s very difficult to lose weight just by exercising, without reducing your calorie intake.
How to Calculate Your TDEE
To calculate your TDEE, you need to know your Basal Metabolic Rate (BMR). Your BMR is the number of calories you burn to perform essential bodily functions such as digestion, respiration, etc. It’s the largest part of your TDEE.
Now, there are several formulas to calculate your BMR. But, we’re just going to give you one formula that is widely used and pretty reliable so that you don’t get confused. It’s the Mifflin-St Jeor equation which was created in 1990.
Here’s the Mifflin-St Jeor equation for men:
BMR = (10 x weight in kg) + (6.25 x height in cm) – (5 x age years) + 5
Here’s the Mifflin-St Jeor equation for women:
BMR = (10 x weight in kg) + (6.25 x height in cm) – (5 x age years) – 161
Once you know your BMR, it’s easy to calculate your TDEE. Just multiply your BMR by your activity factor to get your TDEE. The formula is as simple as:
TDEE = BMR x activity factor
Your activity factor is a number that represents how physically active you are. To find out your activity factor, use the table below:
|Sedentary||Little or no exercise||1.2|
|Lightly active||Light exercise/sports 1-3 days/week||1.375|
|Moderately active||Moderate exercise/sports 3-5 days/week||1.55|
|Very active||Hard exercise/sports 6-7 days/week||1.725|
|Extremely active||Very hard exercise/sports every day and a physical job||1.9|
Now, let’s give an example of how to use the above formulas. Say, you are a 30-year-old woman who weighs 154 pounds (about 70 kg) and is 5 feet and 3 inches tall (about 160 cm). Then, your BMR is:
(10 x 70) + (6.25 x 160) – (5 x 30) – 161 = 700 + 1,000 – 150 – 161 = 1,389 calories per day
Let’s say that you’re a lightly active woman (you do 15-30 minutes of exercise for 1-3 days a week), then your TDEE is:
1,389 x 1.375 = 1,910 calories per day
How Many Calories Should You Eat to Lose Weight?
If you already know your TDEE, it’s easy to find out how many calories should you eat to lose weight. You just need to eat fewer calories than your TDEE.
As mentioned above, by eating fewer calories than you burn, you’ll create a calorie deficit in your body. Your body then will be forced to burn your fat stores to get the calories it needs. When this happens, weight loss occurs.
But, how much calorie deficit should you create? Well, for most people, a safe deficit is between 15-30 percent below your TDEE.
So, using the example above, if your TDEE is 1,910 calories per day and you choose a 20 percent deficit, then the number of calories you should eat in a day is 1,910 – (20% x 1,910) = 1,910 – 382 = 1,528 calories.
Creating a deficit of 382 calories per day doesn’t seem like much, but in 10 days you will create a deficit of 3,820 calories which is already more than 1 pound of fat (1 pound of fat equals 3,500 calories), assuming most of what you lose is fat.
Remember, your TDEE is not static. After dieting for some time, your metabolism may slow down, your BMR may decrease, so your TDEE may also decrease.
If your TDEE drops so that it becomes equal to the number of calories you eat, then you’ll stop creating a calorie deficit. If this happens, you may need to readjust your calorie intake to continue creating a calorie deficit.
Now that you know how many calories you should eat to lose weight, you want to use that number to create a meal plan.
Some people complain that counting calories is tedious. They think they have to count calories every time they want to eat.
Well, that doesn’t have to be the case. You can use that number to create a meal plan for a few days or a week. This way, you only need to count calories when making your meal plan, not every time you want to eat.