First, a diet plan alone is NOT the only thing you need to stay in good health. It may be able to help you take some weight off, but you should add in a daily exercise plan to be sure you keep that weight off. Second, NOT everyone needs a diet plan. For those who just need to shed a pound or two, exercise is the better way to take it off. Third, a good diet plan IS an excellent way to lose weight. In fact, if you choose the right diet plan you may be able to finally get the figure that you want.. The best diet plans will help you to lose weight and stay healthy at the same time. The better plans will also teach you how to keep that weight off and not just lose a few pounds in the short term. Fourth, if you don't choose the right diet it could seriously affect your health. Too many of the latest fad diets are actually dangerous, and some of them are so dangerous that they may land you in a hospital. A good diet plan should never negatively affect your health.