How to calculate your calorie needs
By Coach Fahad Maniar
We’re all aware of calories, and even if we’re not exactly sure what they are (I’ll get to that in a moment), I think it’s safe to say that anyone who is concerned about their weight and body composition appreciates that calories are important to some degree.
What are calories anyway?
Calories are units of energy. In other words, they’re like the currency your body uses to create energy. The currency exchange is the food you eat. Imagine you’re going to Europe on holiday, you’re going to need some euros (in the bodies case, that’s calories) so you trade in your currency for euros (the food you eat). Different countries have different exchange rates and so do different macronutrient types.
The main macronutrient types are Carbohydrates, Fats and Proteins. They yield approximately 4 calories per gram of carbohydrate, 4 calories per gram of protein and 9 calories per gram of fat (fat is the most calorie dense, this is why when you’re watching your caloric intake, you need to make sure you watch your fat intake.
Your body stores calories and uses them as an energy source but your body only uses so much per day depending on various factors such as your age, gender, activity levels etc. If you consistently eat more calories than you expend per day, your body will store these excess calories as fat. If you consume less calories per day than you expend on a consistent basis, your body will attack fat stores for energy.
Now, there’s a lot more body composition than just counting calories. As much as the if it fit your macros pop tart diet has been glorified lately in certain fitness circle, your goal with fitness should be to sustain optimum wellness and performance so not only do calories count but so do the type of calories you consume.
I’m a big advocate of nutrient dense foods that promote good gut health. Good gut health is key to a strong immune system and endocrine system (hormone system) in the body and these are incredibly important to wellbeing as well as physical appearance and performance.
But, the baseline for it all is calories. You can eat all the nutrient dense foods you want but if you consistently over consume calories, you’ll end up gaining weight, period!
So, why calculate calories anyway?
It goes without saying that if you need to eat less calories than you consume to lose fat or indeed, eat more calories than you burn to gain muscle, then it’s important to know how much you need and what deficit or surplus you need to create in order to hit your goals. Most people that we work with need to create a calorie deficit to lose fat, some people need a calorie surplus to gain muscle. If we’re working with some individuals who are at the right body fat levels and are experienced with training, they can do a combination of surplus and deficits to help them burn fat and build muscle. This is known as calorie cycling.
The first thing you need to establish is your Basal Metabolic Rate also known as your BMR.
Your BMR Is the minimum amount of calories you need to eat just to survive. As tempting as it may be to cut calories as low as you can for faster weight loss, it is NOT RECOMMENDED to eat at your BMR or less. I’ve learned how bad that is from personal experience.
What you actually want to do is find your calorie ceiling. Your calorie ceiling is the most amount of calories you can eat whilst still losing around 2-3 lbs per week (in the case of weight loss).
So how do you calculate it?
There are various methods.
To be fair, the easiest is to get an app like my fitness pal to do it for you however, they’re not always accurate as one of my clients was given a ridiculously low number and another was told to eat an insane amount of protein. Granted, the app only gives you what you put in, but it is prudent to understand other methods too.
There are various formulas available for this. Some use your body fat percentage and others don’t. The most popular formula, in my opinion, is the Harris Benidict formula though this doesn’t use your body fat percentage.
We like to work calories out using your lean body mass so knowing your body mass percentage, you can use something like the Katch-McCardle equation to estimate your calorie needs.
I’m going to assume you don’t have that at hand so we’ll carry on with the good old, Harris Benidict formula (and we’ll be using the revised Miffin St Joer version of it too.. yeah it’s complicated, I know but bear with me!).
So, there are a few variables you need to know including your gender, weight, height and age.
The first step is to calculate your BMR. To do this you use the following equation
For Men: 10 × weight in kg) + (6.25 × height in cm) – (5 × age in years) + 5
For Women: (10 × weight in kg) + (6.25 × height in cm) – (5 × age in years) – 161
So, let’s take myself for example. As I write this, I am 72kg, 173 cm and I am a spring chicken at 37 years.
I’d plug that in the formula to look like this:
(10 x 72) + (6.25 x 173) – (5 x 37) + 5
i.e 720 + 1081.25 – 185 + 5
which makes my BMR 1621.25
Now you have your BMR You need to estimate your TDEE, this is your Total Daily Energy Expenditure.
You do this with a multiplied based around your lifestyle.
the following table shows the multipliers
|Little to no exercise||Daily kilocalories needed = BMR x 1.2|
|Light exercise (1–3 days per week)||Daily kilocalories needed = BMR x 1.375|
|Moderate exercise (3–5 days per week)||Daily kilocalories needed = BMR x 1.55|
|Heavy exercise (6–7 days per week)||Daily kilocalories needed = BMR x 1.725|
|Very heavy exercise (twice per day, extra heavy workouts)||Daily kilocalories needed = BMR x 1.9|
(Thanks to wikipedia for this table)
I’m a pretty heavy exerciser with an active lifestyle so I will tame my BMR and multiply it by 1.725
That’s 2796 calories just to maintain weight.
Now we need to create a surplus or deficit based on your goals.
A basic rule of thumb to create sustainable and safe weight loss is to create a calorie deficit of about 500 calories per day. This can be done with food or activity (though a 50:50 combination of both is ideal)
Although this is a very simplistic way of looking at a calorie deficit, it’s a basic rule.
There are a few important things to note, though.
– Hormones play a big part in body composition and the type of food you eat can affect your hormonal response – According to Charles Poliquin who is an expert in his field, it is important to make sure that the calories
– All calories are not created equal and different types of foods will affect your body and hormones in different ways. 100 Calories of something like Jam compared to 100 calories of broccoli will affect your body in very different ways. The goal is to get the right number of calories, yes, but it is also to get the bulk of those calories from nutrient dense foods.