The Chinese Diet Tea for instance has the company that makes it claiming that you can lose a pound a day or thereabouts just by drinking a cup of the tea they sell for as little as $25 a month or so. They also give you a diet patch.
The law just caught up with them and fined them $2 million.
While not every company makes such clearly dubious claims, they do try. According to the Federal Trade Commission, one out of two advertisements by the weight-loss industry tends to be problematic. They'll say things like you can lose a pound a day, they'll say that drinking a cup of tea will work five times faster than if you completely went without food altogether, and so on.