Quacks tell you all the wonderful things that vitamins and minerals do in your body and/or all the horrible things that can happen if you don't get enough. Many claim that their products or programs offer "optimal nutritional support." But they conveniently neglect to tell you that a balanced diet provides the nutrients most people need and that government guidelines makes balancing your diet simple, explains Stephen Barrett, M.D. and Victor Herbert, M.D., J.D.