Reviewed by: Tim Pittorino, BHSC
One of the questions the experts at 12WBT are most often asked is: how many calories should I be eating in a day?
This is especially pertinent if you’re not exercising at all (and, we fully encourage you to at least think about exercising if you’re not!).
The answer depends on a range of factors including your gender, your body mass index (BMI) and your activity levels. If it’s no exercise at all (and we’ll define exercise as at least 30 minutes of something strenuous) it makes it more complex.
How Calories Affect Your Weight
How much you weigh is a result of three main things; your basal metabolic rate (BMR – see below), the number of calories you eat/drink and the number of calories you burn through exercise.
Your BMR is the number of calories your body would burn in a day if you didn’t move at all. The more muscular you are, the higher your BMR is, because muscle mass needs energy just to maintain itself.
That means that you do have some control over your metabolism by developing your muscles.
As for the two other elements of the equation, food and exercise, remember the simple formula: calories in, calories out.
In other words, you need to play around with your calorie intake through what you eat and drink (calories in) and exercise (calories out) to strike the right balance in order to achieve your goals.
And of course, doing more exercise can also affect your BMR as you develop more lean muscle, so it’s a win-win situation.
Calculating your BMR
While BMR is quite a complex beast, here’s a very simple way to gauge roughly what yours is:
BMR = 655 + (9.6 x weight in kg) + (1.8 x height in cm) – (4.7 x age in Yrs)
To work out your total daily calorie needs, multiply your BMR by the appropriate activity below:
- If you are sedentary (little or no exercise) : Calorie-Calculation = BMR x 1.1
- If you are lightly active (light exercise/sports 1-3 days/week) : Calorie-Calculation = BMR x 1.275
- If you are moderately active (moderate exercise/sports 3-5 days/week) : Calorie-Calculation = BMR x 1.35
- If you are very active (hard exercise/sports 6-7 days a week) : Calorie-Calculation = BMR x 1.525
If you’re trying to lose weight, you need to exercise!
When you’re trying to lose weight, you have to burn more calories than you eat and drink. You can do that by cutting calories or exercising. By far the best way to lose weight quickly, efficiently and healthily is to do both.
Simply put, you need to eat less and move more.
This might seem obvious, but so many diet plans try to convince you that you’ll lose weight by cutting out certain food groups.
Forget all that hocus-pocus about “don’t eat carbs” or “only eat protein” and remind yourself: calories in, calories out.
So, every little thing you eat and drink during the day (yes, even if you eat that one little lolly!) counts towards your daily calorie intake. Similarly, every minute you exercise rather than watching TV counts towards your daily calorie burn.
But keep in mind that all the calories you eat and drink aren’t created equal.
When you decide to eat fewer calories for weight loss, you have to make sure you’re not eliminating essential vitamins and nutrients in favour of unhealthy processed foods.
We’ll help you make the right food choices in our article on how many calories you need to eat to lose weight.