All the calories our body needs come from food. When eating, the chemical action of human metabolism decomposes food and converts it into energy.
Daily activities, from breathing to running a marathon, are driven by burning calories.
Combustion heat is one of the metabolic processes. If the body needs enough oxygen, water and food, cells will work actively to burn calories at the best speed. Therefore, a healthy diet, good digestion, proper minerals and vitamins and regular exercise are indispensable.