Less than a year ago, a new generation of diet pills seemed to offer the long-sought answer to our chronic weight problems. Hundreds of thousands of pound-conscious Americans had discovered that a drug combination known as "fen-phen" could shut off voracious appetites like magic, and the FDA had just approved a new drug, Redux, that did the same with fewer side effects. Redux would attract hundreds of thousands of new pill poppers within a few months.
But now the diet-drug revolution is facing a backlash. Some of the nation's largest HMOs, including Aetna U.S. Healthcare and Prudential Healthcare, have begun cutting...