It’s probably the most common question I get, “how much can I, or should I eat everyday?” Now this of course depends on several factors, and estimating the amount of calories you should consume a day is basically a numbers game. While I usually prefer to avoid math whenever possible, I wanted to provide some of the equations dietitians and other health professions use so that you can do the calculations right at home.
The most accurate equation for estimating calorie needs is called the Mifflin St Jeor equation.
Here is the formula:
Male: 10×weight (in kilograms) + 6.25 × height(in centimeters) – 5 × age (in years) + 5
Female: 10×weight (in kilograms) + 6.25 × height (in centimeters) – 5 × age (in years) – 161
The answer to this equation gives you your basal metabolic rate or BMR. The BMR is essential the amount of calories your body burns before any activity is factored in. So the BMR number needs to be multiplied by which ever activity level you fall into.
Activity Factors:
Sedentary (not at all active): multiply by 1.2
Lightly active: multiply by 1.3
Moderately active: multiply by 1.55
Very active: 1.725
Extremely active: 1.9
Example: A female that is 30 years old, 67 inches, 150 pounds and walks 5 times a week would have a calorie budget of 1863 to maintain weight and 1363 calories to lose weight.
The calculations look like this:
First, figure out weight in kilograms by dividing your weight in pounds by 2.2 (150 /2.2 = 68.1)
Next, determine height in centimeters by multiplying height in inches by 2.54 (67 × 2.54 = 170.1)
Then, plug in the numbers
= (10 × 68.1) + (6.25 × 170.1) – (5 × 30) – 161
= 681 + 1063 – 150 – 161
= 1433
Then take 1433 × 1.3 (because she is lightly active)
= 1863
So she can eat about 1863 calories to maintain her weight and I subtract 500 calories if she wants to lose weight, giving her a calorie budget of about 1363 calories per day
Now, if all of this math stuff isn’t your thing, there are several great websites that do all the work for you. In fact, Vital Choice actually has a health calculator section that can tell you everything from ideal body weight to target heart rate and more! So check them out and see if you’re on the right track to health and well being.
–Nicole Gould, RD LD
