About 127 million Americans, that's over 60% of all adults, are overweight. I'm sure that all these people don't want to be overweight, and a lot of them are probably trying their hardest to get it under control. Yet, for whatever reason, it just doesn't work.
I suspect the real problem is that the vast majority of fad diets, are just that - fads. They may work for the first week or so, but after that you would be better off if you had never started. You can spend years trying hundreds of different fad diets before stumbling on one that really works.
If you want to really lose weight, you need a way to guess whether the diet will work for you, without having to go through the hassle of buying it and spending a month trying it out. Here I'll tell you what to look for in the advertising spiels so you can tell the fake from the functional.
The very first thing to take a look at is the guarantee they provide. If there isn't any guarantee, or they only offer you a very short one, don't take it. However long they promise it will take for you to notice the effects, I suggest you make sure the guarantee is for double that long. You don't want to have the diet fail you right after the guarantee expires.
Besides the guarantee, you should also look at how much time you need to notice the effects. Surprisingly, the longer this time is the more likely the diet is to be real. If they say anything more then 10lb a week, I'd get suspicious. The best diets usually offer 5lb or less weight loss per week.
How fast can you safely lose weight? 14lb in 14 days is of course possible, but it's a terrible idea, and it is certainly not possible to maintain it. The best diets will not give you any guarantees of time or weight, because everyone is different, and there is no way to know for sure how fast someone will lose weight, no matter how good the diet may be.
Of course, not every diet is like this. Sometimes, you can lose weight very quickly. For instance, I knew a woman who wanted to lose 60 pounds. She started going to the gym every day, and working out hard for three hours. At the end of the first week, she had dropped 20lb. Now, that's rather a special case, but it shows what can be done. these diets aren't telling you to work out though, they're telling you to sit at home and eat. To me, that seems like a bad idea. It's just common sense - food goes in, you never use it, what happens?
If they say you don't need to worry about the amount of food you eat, then it's either a scam, or they want you to gorge on completely non-nutritious foods so that you feel full, while getting absolutely no benefit. that is incredibly unhealthy, and can often cause serious permanent health problems, much worse then just being overweight.
If any dieting scheme promises slow constant weight loss, with a reasonable timeframe, then it's probably real. If they offer a good mix of workouts and recipes, then it just might be worth giving a try. Just make sure you stay clear of anything telling you to avoid a food group, no god can come of that. There's no magic bullet for weight loss.