I wish it worked like that. Unfortunately, it's just a sales pitch. You'll lose some water weight, which will come back in a day or two. It has no effect on the fat in your body. It also has no effect on "toxins" because we don't really store toxins. Our bodies do a very good job of eliminating the things we don't need. The threat of "toxins" has been used for pitching a lot of unnecessary products because it sounds scary.
Our bodies change as we age. You might have been a few sizes smaller, but maybe you had more lean mass then and more fat now, which will do that. There are a lot of things that could have happened since then to change your size/shape without changing your weight. I know that no matter how much weight I lose, my butt will never be as small as it was in high school