First, the promotion of diets has gradually changed the social conceptions upon what is the real beauty. The advertisements try everything they can to advertise that using their products can make the customers become more beautiful, and the effects of using it is to become slimmer. Nowadays, a large amount of people think that being slim is the only criteria to judge whether a person is beautiful or not, despite the human beings' natural beauty. And it is so unfair to fat people to be thought ugly.
Second, the promotion of diets tend to make people ignore that being on a diet, if in an inappropriate way, can do great harm to the dieter. They tend to try every possible way to lose weight, including taking untested diet pills, stop eating staple food for a couple of weeks, etc. Those so-called effective ways obviously do a great harm to the dieters, and the outcome of doing so may not always result in happy ending. The conception those promotions have changed amid people's mind may easily harm themselves.
Third, the medicine sold on market for losing weight have been too much, and if not banned, they may even grow bigger later. Much of the diet pills have not gone through medical test, or unlicensed at least, it cannot be sure what kind of effect it really would bring to people who take them. So there exist a necessity that the promotion of diets should be banned.
I agree with what others have said, I don't find anything wrong with dieting or trying to improve your health etc. But there is definitely a problem with people making millions of dollars off of people who are self-conscious or have low self-esteem and just get sucked into something they think will change their lives forever.
There is nothing wrong with wanting to lose weight. Every one should take care of themselves. I have a problem with making a multimillion dollar industry out of self conscious people especially in America. Advertising diet plans enables the rich to come up with lose weight fast schemes that don't work but cost money.
Diets should be promoted just like everything else is. It'd be extremely unfair to simply ban diets from being advertised while other things such as cigarettes and alcohol become widely advertised throughout television and in billboards. In fact, they are even advertised on the radio, so diets have every reason to be promoted.
I personally feel we live in a society that relies too much on governing bodies to restrict those things that could be bad for us. In doing so, we allow someone else to make our personal choices for us, and while this may be fine for some, it inevitably leads to problems on the individual level. With this in mind, I see no reason to ban the promotion of diets. While many promoted diets may not be the best health wise, that is no reason to take that choice away from an individual. Who am I to tell you that you cannot follow the South Beach diet or some variation thereof? Some people for health reasons need to be on a diet just like this. For others, it may cause health problems.
Preferably, I'd like to see the effort and money that goes into banning things people see as "bad" go towards the promotion of healthy alternatives. Perhaps if people were bombarded with information about other diet options they would not fall for a potentially unhealthy diet.