100kj equals 23.89 calories. 1. The kilojoule is the international unit of calories and work done and is also used to measure the amount of calories contained in food. The human body is able to control its weight by calculating the number of calories burned through exercise and by controlling the number of calories consumed through food. A calorie is also a unit of calorie, generally one hundred kilojoules is equal to 23.89 calories. 2. In our daily life, we can calculate the total calorie intake of food and the daily calorie consumption of the body to achieve the purpose of weight gain and weight loss; those who need to increase their weight should have a total daily calorie intake greater than the amount consumed, and those who need to reduce their weight should have a total daily calorie intake less than the amount consumed. People who need to control their weight should adopt a healthy and reasonable approach.