“lesson is clear: once we enter a specific range of strenuous exercise, the body kicks in to lose fat no matter what our genes want. Bouchard’s groundbreaking work tracing genetic aspects of fat in the 1980s and 1990s depended on observations of physical traits within families; statistical modeling to account for variables such as gender, age, energy intake and expenditure; and human experimentation confined to pairs of identical twins. But new technological advances are now allowing for more specific investigation of”