1. I doubt that if the show were watched in its entirely that you would see the First Lady saying "Absolutely" directly after that statement. That looked edited to me.
2. I know this is a hot button issue for a lot of people, but I don't see many fit individuals as I travel around for work (and I think I can tell the difference between a big strong man and a big fat man). I feel that, especially with the explosion of video games and 1000s of channels of programmin, that there is, in particular, a generation and a half of men/boys and women/girls who do far more sitting, eating and drinking than ever before.
I wouldn't call this a national security risk, but given that we all pay for each other's health care in one way (higher premiums to cover the uninsured) or another, I don't see how "scaring people" into action is necessarily a bad thing, especially if the end result is more people in better shape.
You'd be surprised (or maybe you wouldn't) at how many very obese people in my family or friend's families try to assure themselves around the current state of their health with statements like "I'm big boned." Er, NO.
(the above statements are made outside of the context of silly metrics like BMI)
Complication makes it easy to explain failure.