The four types of dieting
There are four basic types of diets. Several studies have shown that all four are equally as effective, with participants losing between 4-10 lbs on the diets.
Low-carbohydrate diets restrict caloric intake by reducing the consumption of carbohydrates to 20 to 60 g per day (typically less than 20 percent of the daily caloric intake). The consumption of protein and fat is increased to compensate for part of the calories that formerly came from carbohydrates.
This diet is thought to have been the diet used by early humans when we were hunter-gatherers. It wasn't till the agricultural revolution that we introduced mass quantities of carbohydrates.
Low carb diets are commonly used for treatment of diabetes. The reason for this is the relationship between carbs and blood sugar levels. Carbohydrates causes substantial insulin production, and thus tends to store excess energy in the form of fat.
When starting this diet, there is initially a two week period of weight loss caused by eliminating water retained in the body. This is a short term effect and unrelated to actual weight loss by reducing body fat.
Studies have shown no weight loss from this diet unless the intake of calories are also reduced.
The low fat diet is simple. Reduce the amount of fat consumed. While calories are not intentionally reduced, by the act of removing high fat foods from the diet, calories are usually reduced.
Studies have shown approximately 7 lbs weight loss by participants within a 2 to 12 month period.
By reducing the amount of calories injested, the goal of this diet is to force the body to burn the calories stored in the body's fat. Typically this means 1,500 to 1,800 calories allowed per day.
Studies have shown approx 20 lbs weight loss within a 3 to 12 month period. It isn't all fun and games, as a there is the possibility of side effects including fatigue, nausea, diarrhea, and constipation. However, the side effects do tend to disappear over time.
Very low-calorie diets
A very low-calorie diet is any diet plan that allows 800 calories or less in a day. This type of diet is much more agressive than any of the previously listed diets, and should only be done if your diet is overseen by a physician. Dieters typically lose 3-5 pounds per week on this diet. Very low calorie diets are not recommended for general use as they are associated with adverse side effects such as loss of lean muscle mass, increased risks of gout, and electrolyte imbalances.
It is difficult to describe this diet in detail as as the diet is formulated by a physician for each individual's specific needs.