Why do lots of my boomer friends look a lot heavier than their parents did at their age? Food? Exercise? Other?

Many reasons. Thanks to vaccines & antibiotics, baby boomers are living longer & perhaps healthier with less infectious disease/illnesses. Chronic disease are developing later in age. Quality of life is much improved-less disability. Perhaps we should indeed thank medical technology and improve nutrition/public health initiatives (less tobacco use). Unfortunately, statistics reveal more obesity/sedentary ways.