You have to have a pretty cock-eyed view of the world to think that a fairly large change in the skewness of the weight distribution isn't significant. And, yes, it is fairly hard to loose weight, but that has nothing to do with why people weigh what they do in the first place.
>He's saying the tendency toward obesity or leanness is shaped by genetics (duh).
And overlooking that there is a meaninful trend over time, which is clearly false. But this also lets him ignore that the relative cheapening of calorie-dense foods (ie happy meals, cheetos, etc.) has nothing to do with it. Even neo-classical economics tells us that it would have a lot to do with it.
Christian