By Chris Adams

Ian R. Lanza, a professor in endocrinology at the Mayo Clinic College of Medicine, detailed in depth the biology of obesity – and how changes over the past half century have transformed American’s bodies.

“We’ve managed to engineer physical activity out of our lives,” said Lanza. His research examines the impact of lifestyle factors such as exercise and nutrition on skeletal muscle function, energy metabolism and adaptations to exercise.

In his talk, Lanza defined the apple- and pear-shaped body types, explaining why fat stored in those apple shapes is more dangerous. He explained why the enormous amounts of fat on sumo wrestlers isn’t a risk when they are competitive athletes – but why it is a risk later when their wrestling days are done. And he explained what he called a “vicious cycle” of that starts with nutritional excess, leads through protein and DNA damage, and ends in impaired muscle function and physical inactivity.