That's interesting if the CDC mandated a certain BMI. I would comply. Though I qualify as I am right now so I wouldn't have any issues. But I wouldn't support such a measure. Being fat doesn't effect others health and is a personal freedom. Much like abortion, smoking, drinking, sex etc.
Mandated?
Under whose authority?
What would be the means of enforcement?
Maybe they can mandate birth control to reduce abortions?
Or mandate a vegan diet to reduce red meat diet related health problems?
Or brushing your teeth 4 times a day to prevent tooth and gum problems?
How about mandating breast feeding because it's better for the baby?
Or 1 hour daily of exercise for everyone over the age of 3?
Ban every sugary soda, ice cream, cake, pie, cookie, candy bar and dessert, too.
Why stop at just weight? If you really want everyone to be safe and healthy, take away ALL CHOICE and mandate everyone live as you deem healthy.