As a matter of fact, these diets don't usually consider the build and the age of the reader. Most of these diets do not follow common sense rules at all and should only be used as non-specific schemes of nutrition.
Unfortunately, these diets are often used by the readers "out of the box" without any adjustment or attention to their individual biological or psychological differences. Also, these diets are often designed to achieve fast results in terms of weight reduction, but very poor results in terms of long time maintenance of any weight loss achieved.
The best way to get a diet of your own is to see a dietician. The dietician will help you to define your goals and to keep these goals realistic, and will reinforce your wish to change your bad eating habits as well as your life-style.
Moreover, being followed-up by a live expert who can answer your questions and correct your misconceptions about food and eating, and having someone who can supervise your results, will be much stronger motivating factors than the paper experts who write slimming diets in women's magazines.