Why 95% of diets fail to achieve their goals

The dismal statistics about diets indicate that 95% of them fail miserably. People may manage to lose a little weight in the beginning of the diet, though most of it is just liquids and not fat, but most of them stop losing weight after a while, gain back what they lost and even more, so that they end up fatter than they were to begin with.

Why is it that most diets fail and what sort of diet should we use to avoid the same fate and achieve a fast and continuous weight loss?

The main reason why most diets fail is that they are based on a greatly reduced calorie intake and/or a total avoidance of a certain food group. A low calorie diet, and I have seen people go on 400 calories a day diets, causes your metabolism to slow down considerably and your body to burn less and less fat.

You see, the body protects itself because it thinks you're starving it.
When you stop the diet and start taking in more calories, your metabolism is still low and you gain much more fat. And besides, eating 400 calories a day is very hazardous to your health.

Those diets which tell you to stop eating a certain food group like no-carbs or no-protein diets, hurt the body because they deprive a necessary ingredient from it. They may be very dangerous to your well-being. Any weight loss achieved through them is of short term. What you need is a diet which lets you eat a reasonable amount of food with a certain supply of all necessary food groups that still helps you to lose weight.
A diet like Fat Loss 4 Idiots which is based on Shifting Calories is the best bet as it does not starve you but produces a fast and continuous weight loss.