How do calories work?

You will have seen the influx of calorie comparisons and overall awareness of calories nowadays. Public health initiatives are pushing them, restaurants are having to share this information with their customers, and we are finally getting lower calorie ice creams, beverages, and even alcohol! Oppo ice cream is the best!

But how do calories work? What are they? And why do we need to consider them?

Calories are a unit of energy. They are used to establish the amount of energy a certain food product contains, and also how much energy we as humans are burning at rest, during exercise and across other various tasks. This is where the Calories IN vs Calories OUT equation comes from.

With regards to food products, calories can be broken down further into where they come from. Macronutrients. Or ‘Macros’ if you’re in with the lingo. Protein, carbohydrate, fat, and ethanol (alcohol) is where energy can be derived from. Each one of these constituting a certain amount of calories per 1 gram:

Protein – 4 calories per 1 gram

Carbohydrate – 4 calories per 1 gram

Fat – 9 calories per 1 gram

Ethanol – 7 calories per 1 gram

So think of calories as the primary figure. The macronutrient content of a meal, food, or drink, is what will determine that calorie number. For example a meal consisting primarily of protein and vegetables is going to be less calorie-dense than a meal with protein, carbohydrate, and fat in there. Hence why the ‘low-carb diets’ and the ‘low-fat diets’ get results.

BUT, this doesn’t mean you have to be extremely restrictive with your diet to get results. Simply knowing the number of calories you need to be eating per day, and then offsetting it against the number of calories you are ingesting per day, is where you can start to play with your food sources and the composition of your meals.

Depending on your goal, whether it be weight loss (eating less than you burn) or weight gain (eating more than you burn), your required calorie intake can be established accordingly:

How many calories do you require to maintain weight?

Bodyweight (KG) x 22 x respective activity factor

Activity factors:



1.6 Train hard/OFFICE JOB



Once we have established your maintenance calories we can start to play with the deficit/surplus depending on your overall goal:

Steady weight loss – 10% of your maintenance calories

Faster weight loss – 20% of your maintenance calories

Steady weight gain + 10% of your maintenance calories

Faster weight gain + 20% of your maintenance calories

Now how many grams of protein? For now this is the only macronutrient worth worrying about. The rest of them you can be flexible with so long as they fit within your remaining calories. I recommend your protein intake to be 1.8 – 2 grams per kg of body weight per day. Remember whatever that is multiply it by 4 and that is your calories from protein per day. The remaining can be filled with fats, carbohydrates, and even alcohol if that’s a bit of you.


So this is what calories are, this is how we work out how many we need to be eating to get the results we want. And it really is that simple. You will probably want to use an application like MyFitnessPal to monitor your intake, however, make sure you input your custom calorie requirements based on the numbers above. MyFitnessPal does some funky calculations for calorie and protein requirements. Otherwise, there is a pretty decent program called The MS Method which will provide you with all the necessary ;).

Let us know if you have any questions!

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