The calorie theory is as follow

The calorie theory is as follows :

If a particular individual needs 2,500 calories a day and consumes only 2,000, a 500 calorie deficit results. To compensate for the deficit, the body will draw on its fat reserves to find an equivalent amount of energy, and weight loss will result. If, on the other hand, an individual has a daily intake of 3,500 calories when only 2,500 are needed, the excess 1,000 calories will automatically be stored as body fat.

The theory is therefore based on the assumption that there is no loss of energy. It is purely mathematical, drawn directly from Lavoisier's theory on the laws of thermodynamics.

At this point we may well be wondering how it was that prisoners in Nazi concentration camps managed to survive for almost five years on only 700 to 800 calories a day. If the calorie theory was correct, the prisoners should have died once their body fat was used up in other words, within a few months.

Similarly, we may wonder how people with big appetites who consume 4,000 to 5,000 calories a day are not fatter than they are (some even remain skinny). If the calorie theory was correct, these hearty eaters would come to weigh 60 to 80 stone within a few years.

Furthermore, how can you explain why some people continue to put on weight even when they reduce their daily calorie intake by eating less? Thousands of people go on gaining weight like this while starving themselves to death.