"We've become accustomed to a kind of comfort level in knits."
But the devil is in that forgiving detail of stretch, Kelly said.
"It's very easy in this country to do two things," he said. "One: overeat. Two: wear really comfortable clothes. The problem is, when you combine both of those things you get caught in a spiral."
Large portions of cheap, overly processed foods keep us wearing stretchy, knit clothes -- that makes it easier to eat more large, overprocessed portions.
"I've heard this from women time after time: 'Before you know it, you've gained 30 pounds.' And then you get to a point where it's hopeless -- 'I can't lose 30 pounds.' "
"You say, 'Uh, I give up,'" he said. "'I'll keep wearing my big comfy pants.'"