It isn't the diet design that's bad, it's the inability of people to follow those diets.
A new study has indicated that the success of a diet depends much more on whether you stay on it rather than what type of diet you are one, say researchers from the Tufts-New England Medical Center, Boston, USA.
You can read about this study in JAMA (Journal of the American Medical Association).
In this study, led by Dr M Dansinger, 160 people were on a diet.
They all had either hypertension or high cholesterol levels (they were all overweight).
Some were on the Atkins, The Zone, Weight Watchers or the Ornish diet.
The researchers monitored these people for a period of one year.
At the end of a year the researchers assessed how much weight they had lost and whether (how much) their health problems had improved.
All the diets showed similar cardiovascular and hypertension (blood pressure) benefits.
All the diets showed similar success and failure rates (number of people who dropped out or stuck to it).
Experts say that losing weight, keeping it off and staying (getting) healthy is a question of adopting a permanent lifestyle.
The dieter has to adopt a lifestyle he/she can sustain for the rest of his/her life.
Possibly, the greatest secret in losing weight, maintaining ideal body weight and staying/getting healthy is to do things in moderation.
Eat too little and you will not be able to sustain it - when the diet breaks, all the weight comes back plus more.
Other studies have shown that physical activity can be an even greater contributory factor to achieving good health and your ideal weight.
Many people who exercise regularly enjoy good health, even if they are not too careful about what they eat.
Of course, the ideal situation is to eat wisely and also take part in physical activity.