A lot has been talked about calorie shifting diets to lose weight rapidly. The theory behind these diets are that you basically spend one day on a very low calorie diet, around 400 calories or so, followed by a day taking in a normal amount of calories. As a result, your body does not adapt by reducing its metabolic rate which makes losing further weight more difficult as you may have found on conventional diets. On a conventional diet it only takes between 2 to 3 days of consecutive low calorie eating for your body to go into starvation mode and reduce its metabolic rate. Also form an emotional point of view you only have to diet every other day rather than every day.
The disadvantage of a calorie shifting diet are that you can feel very hungry on every very low calorie day. Compared to a normal diet after about 5 days of dieting your appetite normally diminishes. This does not happen with the calorie shifting technique. Another disadvantage which many may find an advantage is that you can lose weight very quickly with this method. If you are a body builder this could send you into a catabolic state causing you to lose lean body muscle mass as well. Also losing weight rapidly is not healthy. It can lead to fatigue, dizziness, nausea and immune system deficiencies. The latter can lead to infections, particularly skin infections and cold like infections.
With this sort of diet it is important to take a regular multivitamin and to get enough sodium and potassium to prevent getting lightheaded or dizzy. A good way to overcome this is to drink 2 oz cans of tomato juice a day. If you are a bodybuilder or fitness model, you will also want to consume enough protein on your low calorie days. This can be achieved by eating a few egg-whites and a small amount of lean chicken or fish.
This diet is not aimed at being a long term diet, more of a way to lose fat fast. It is also important to remember that after losing weight on a calorie shifting diet it is easy to put weight on after finishing so you still need to continue calorie counting.