When you are on a crash diet, you reduce the calorie consumption in the body substantially. This if continued helps you reduce anything between 2 to 5 kilograms within a week.
This seems to be going fine but what actually happens is that when the body is deprived of those extra calories, then the stored food component of the body in the form of glycogen is used up.
This causes the body to lose water and hence the immediate weight loss is seen. There are a number of health risks that are involved because of the drastic cut in the diet. The vitamins and minerals that you would have had otherwise get cut down in content.
The body starts using up mass from the tissues to make up for the lack of energy when one is on a crash diet. This happens more quickly than it would have under natural circumstances, rendering the tissues more susceptible with an immune system that does not work that well.
There is a cycle that occurs during crash diets. There is a period of tremendous weight loss and then there is a period of intense hunger and hence a sharp weight gain. While the body has lost more weight than the metabolism is prepared for, there comes the possibility of the cholesterol levels increasing in the blood, therefore increasing the risk of a heart disease also.
Such diets are known to weaken one’s immune system. This is not only because of the nutritional deficiencies in the diet, but also because the body tries to cope with a sudden loss of mass with the body’s reserves being put into use and the metabolism of the body trying to sustain the body parts accompanied by the extra pressure on the immune system to keep them healthy too.
Moreover, those on a crash diet tend to be irritable and lethargic due to the sudden loss of energy. There is a tremendous hunger craving that diverts attention constantly.