Calories and kilojoules are both units of energy that are used to represent the amount of energy in a food.
1 Calorie is equal to 4.18 kilojoules. Therefore 1 kilojoule equals 0.24 Calories.
To convert the Calorie content of a food into kilojoules, multiply by 4.18.
To convert the kilojoule content of a food into Calories, divide by 4.18.
For example, 100 calories multiplied by 4.18 is 418 kilojoules.
418 kilojoules divided by 4.18 equals 100 Calories.
We will use kilojoules as the unit of measurement in this blog.
Food Energy: Food is made from macronutrients.
Each of the three macronutrients — carbohydrates, proteins, and fat — contain a different amount of energy per gram of food.
Carbohydrates contain 16 kilojoules per gram.
Protein, 17 kilojoules per gram.
And fat, 37 kilojoules per gram.
The total number of kilojoules of a food item depends on the proportion of carbohydrate, fat and protein present in the food and the serving or portion size.
When we compare the amount of kilojoules between foods of the same weight, volume or serving size we are looking at the energy density of foods.
The energy density of a food item is dependent on its macronutrient composition.
Foods that contain larger amounts of fat, such as chocolate, have a higher energy density compared to foods that contain more protein or carbohydrate, such as strawberries.
100 grams of chocolate has far more kilojoules than 100 grams of strawberries.
On average, it is recommended that males eat around 9900-12700kJ per day and females eat around 7600-9800kJ per day to maintain weight.
For weight loss, men and women need to eat less than those amounts.
The exact requirements for men and women depend on a number of factors like height, weight, and physical activity level.