I know I’m going to get some hate for this, but the term ‘listen to your body’ should be thrown out the window when it comes to weight loss.
To lose weight effectively (meaning a minimum loss of 0.5kg a week) we must track our caloric intake and expenditure. If we do not monitor our caloric intake and expenditure, then it can become difficult to know if we have finished our day in a caloric deficit – a pre-requisite for weight loss.
What is a caloric deficit?
A caloric deficit is the “magic” that makes weight loss possible. It simply means consuming fewer calories we expend in energy throughout the day. By falling into a caloric deficit, we can force the body to use fat stores for energy and thereby lose weight.
How can I create a caloric deficit?
It seems simple, but the number of calories you need to lose weight, maintain weight, or gain weight depends on your activity levels, gender, height and current weight.
To calculate your caloric deficit, you first need to determine how many calories you need a day to maintain your current weight. For an exact number, we need to start by calculating your Basal Metabolic Rate or BMR.
How to calculate your Basal Metabolic Rate
Your Basal Metabolic Rate, or BMR, is the minimum number of calories that your body burns at rest and accounts for roughly 60-75% of your total daily caloric burn.
An extensive study published by the Journal of the Academy of Nutrition and Dietetics found the Mifflin-St. Jeor equation to be highly accurate, so it is considered the gold standard when it comes to calculating BMR.
For women, the Mifflin-St. Jeor equation equation is: BMR = (10 x weight in kg) + (6.25 x height in cm) – (5 x age in years) – 161.
For example, I am 28 years old, 5’0″ tall and weigh 113 pounds. Therefore my BMR equation would look like this:
BMR= (10 x 51.2) + (6.25 x152) – (5 x 28) -161 = 1,161 calories
After calculating your BMR, we need to take into account the activity that you do throughout the day such as walking the dog, laundry, or the climbing stairs to your apartment.
To do that, multiply your BMR by the factor that best represents your activity level:
- If you are sedentary multiply your BMR by 1.2
- If you do light exercise 1-3 days a week multiply your BMR by 1.375
- If you exercise at a moderate intensity 3-5 days a week multiply your BMR by 1.55
- If you exercise at a high intensity 6-7 days a week multiply your BMR by 1.725
- If you exercise twice a day or have a physically demanding job multiply your BMR by 1.9
I, for example, am very sedentary today, being that it’s a Sunday and all I plan on doing is smashing out a few blog posts, so my calculation will be 1161 x 1.2 = 1393.
Therefore I will need to consume 1393 calories today if I am to maintain my current weight. It might not sound like very much, but remember I am only 5ft nothing, so yours will probably be higher.
Want to make the calculation even more accurate?
If you have a set of scales that calculate your BMR, body fat, muscle mass, water weight, and much more, you can also factor its calculation into the equation.
For example, my smart scales tell me that for my proportions I need to consume 1248 calories a day to maintain my current weight.
Therefore, to make the above calculation a little more accurate, I take the medium between the two; which takes my BMR down to 1320.
It can be challenging to get an exact number as even the expensive body scanners can produce varying numbers, so we are just trying to be as accurate as humanly possible even though there may be some variation between scales and calculations.
Okay, so now that we have our BMR, how many calories do we need a day to lose weight?
Once you know how many calories you need each day to maintain your weight, subtract your chosen number of calories to put yourself into a caloric deficit.
How many calories?
Well, to lose roughly 0.5kg a week (a healthy goal) you’ll need a 500-calorie-per-day deficit. We could do this in three ways:
- If you plan to have a lazy day around the house and do nothing but watch Netflix, then take 500 calories from your total daily caloric intake.
- If you are attending a gym class or going for a short run, or are generally moderately active, then we can take 250 calories from your total daily caloric intake and burn 250 through exercise.
- If you are planning to be very active like going for an hours run for example, then we could use your run as your total caloric deficit if it hits the 500 calorie mark.
Put simply, your goal is to finish the day in a 500 caloric deficit; it doesn’t matter too much how you get there.
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