Is your shampoo making you fat?
For years, the explanation for weight gain was straightforward: it was all about energy balance, or calories-in versus calories-out. This Gluttony and Sloth theory held that obesity simply came from overeating and underexercising, and the only debate was about dieting — whether it was better to join the low-fat or the low-carb camp.
Some scientists explored genetic differences associated with fat, but others said genes couldn’t possibly explain the rate at which Americans were gaining weight: “We just aren’t evolving that fast,” one obesity expert noted.
