The burning question is, how many calories do you need?

very little energy to digest. Carb TEF is between 5% & 10%, requiring a little more energy to digest. Protein TEF is the 20-30% requiring most energy to digest.

What is a calorie? A calorie is a unit of energy equivalent to the heat energy needed to raise the temperature of 1 gram of water by 1 °C.

To now understand how we gain or lose bodyfat, I’ll use a simple analogy. Think of a full bucket of water under a running tap with a hole in the bottom where the water in the bucket is your stored bodyfat and the water entering and leaving the bucket is calories. If the amount of water going into the bucket is the same as the amount going out the hole in the bottom, the water level will not change. This represents your Maintenance Calories, which is the daily calories you need to maintain your current bodyweight. If you turn the tap off just a little, the water level in the bucket will slowly drop. This represents fat loss where your body has to use some of your stored bodyfat to maintain your TDEE.

Conversely, if you turn the tap on a little more, then the bucket will start to overflow. This represents fat gain where your body has more calories than it needs and stores the excess energy from those extra calories as bodyfat.

Now we get to the burning question. How do you calculate your Maintenance Calories? Thankfully there are lots of free calculators online but I will give you a simple and effective way to do it using the Harris Bennedict method and your phone calculator:

STEP 1: DETERMINE YOUR BMR AS EXPLAINED ABOVE:

MEN: BMR = 66.5 + (13.75 x weight in kilos) + (5 x height in cm) – (6.75 x age in years)

WOMEN: BMR = 655.1 + (9.563 X weight in kilos) + (1.85 X height in cm) – (4.676 x age in years)

To determine the calories you need on top of your BMR, you need to multiply it by your activity factor:

STEP 2: TAKE THE BMR NUMBER AND MULTIPLY IT BY THE APPROPRIATE ACTIVITY FACTOR BELOW:

SEDENTARY: little or no exercise (BMR x 1.2)

LIGHT ACTIVITY: light exercise/sports 1-3 days/week (BMR x 1.375)

MODERATELY ACTIVE: moderate exercise/sports 3-5 days/week (BMR x 1.55)

VERY ACTIVE: hard exercise/sports 6-7 days/week (BMR x 1.725)

EXTRA ACTIVE: very hard daily exercise/ sports & physical job (BMR x 1.9)

To show this formula in action, let’s use our fictious friend John. John is 35, weighs 85kg, is 176cm tall and has an activity factor of moderately active:

John’s maintenance calories = 66.5 + (13.75 x 85) + (5 x 176) - (6.75 x 35) = 1,879 (BMR) x 1.55 (activity factor) = 2,912

Therefore, to maintain his current bodyweight John should consume approx. 2,912 calories per day.

Please keep in mind that this is just an estimate and should be used as a guideline and not an absolute rule but it gives you a good starting point when planning your meals and calories.

If your goal is to lose some bodyfat, then you could start by calculating your maintenance calories and introducing a small deficit and see how you get on by monitoring your weigh and how your clothes fit but please speak to your GP or a health professional before making any significant changes to the amount of food you eat.

When it comes to weight loss, less is not more, so in my next article I’m going to explain how you can reduce bodyfat in a controlled and healthy way and maintain a healthy bodyweight. I will also explain how to avoid many of the dietary pitfalls people fall into such as, undereating, crash dieting and how that can actually prevent you from losing weight and be detrimental to your health.