While they were happening, the '80s seemed so darned healthy. Joggers and bicyclists clogged the pathways. Exercise spas threw open their glass doors and mirrored chambers. Folks didn't just watch their weight, they also enrolled in diet movements, diet 12-step programs and diet franchises complete with celebrity TV endorsements and calorically correct prepackaged snacks, meals and desserts. Even the Christmas turkey seemed somehow leaner.
But when scientists finally put a representative sampling of Americans on the scale, the decade's secret scandal was uncovered: rather than getting healthy in the health-conscious '80s, Americans actually plumped out. It's not just that individuals got...