Because high fat foot is, like, still food?
You're saying that it has to do with it's nature? Last time I checked marijuana was quite natural, the items origin or substance has nothing basely to do with it's illegal status, it pertains with the harmful effects. It's not unfathomable that they would ban tobacco, banning high fat food is in the exact same field, it just happens to be less easy for the public to swallow so it's not something that's been done, although it very well could happen, the morality behind one is the same for the other...
Is there really a defining difference between something like food or the illegal psilocybian mushrooms (a.k.a. shrooms (although legal in certain places as with many things))? They're both edible substances that have negative effects? In fact, I would say that is a food source being banned right there.
Seatbelts are not only for your own protection, but for the protection of others from you.
So it could be justified but that's hardly near a main intent, perhaps the graph of deaths caused by "body shrapnel" could be shown..? I think the evidence behind the harm of second hand smoke is laughable, I can't even say how I feel on this, unless you had a different meaning?
How far would they have to go in order for you to pay attention? If it's banning unhealthy food or similar, then I suggest taking a look around, as that's practically what's been done now...