Much research has proven that dietary fat is not necessarily converted into body fat. Carbohydrates, on the other hand, are readily converted into fat by the action of insulin. According to many experts, most overweight people became overweight due to a condition called hyperinsulinemia -- elevated insulin levels in the blood. When you eat a high-carbohydrate meal, the increased blood sugar stimulates insulin production by the pancreas. Insulin is the hormone that allows blood sugar to be used by the cells. However, a side effect of insulin is that it also causes fat to be deposited, and it stimulates your brain to produce hunger signals. So what do you do? You eat more carbohydrates, and the cycle repeats. In time, your body cells become resistant to insulin, meaning that your pancreas has to work overtime, producing up to four or five times as much insulin just to keep up with the demand. It has been shown that high levels of insulin have a deleterious effect on the body, including premature aging.

Restricting the intake of carbohydrates puts a halt to this vicious cycle. When you restrict your carbohydrate intake, your insulin levels decrease and the levels of glucagon increase. Glucagon is a hormone that causes body fat to be burned and cholesterol to be removed from deposits in the arteries.

If you severely restrict carbs, your body goes into a state of ketosis--burning fat with the subsequent production of ketone bodies in the bloodstream. The condition is called "ketonuria" if ketones are spilled out into the urine. The result of ketosis is that your blood sugar levels stabilize; your insulin level drops; and because your body is burning fat, you lose weight! You can easily test to see if your diet is inducing ketosis with the use of inexpensive ketone test strips.

When your diet causes your body to go into a state of ketosis, you are said to be on a ketogenic diet. For most people, restricting your carbohydrate intake to fewer than 30 grams a day will induce ketonuria. Most people on ketogenic diets lose weight fairly quickly. However, although some diet experts believe that ketosis is a safe condition, it is not necessary to be in ketosis to lose weight. Keep in mind, however, that when you choose a higher level of carbohydrates than what is needed to bring on ketosis, you may have to limit your total food intake (calories) somewhat in order to lose weight.