One of the reasons that obesity is prevalent in the USA is not because of overeating, but rather from undernourishment - there is not enough nutritious content in the food that people are eating. Some are putting this down to the lack of minerals in our food - a direct result of the deficiency of minerals in our soil, which passes on the deficiency to the food it is supposed to nourish, which in turn is supposed to nourish us.
The amount of trace minerals that the body needs is very small, but the effect that they have on the body is immense. High doses can be dangerous, so it is always wise to tread gently with these kinds of supplements. If you are a fast-paced careerist who is always on the go, it makes sense to supplement your diet with trace elements, but nothing beats a healthy, home-grown organic diet with plenty of fruits and vegetables.