Not necessarily. Being told at gunpoint (the ultimate endpoint of any "law") that smoking is "bad" and potatoes are "good", is bad. Freedom to choose is good.
If you like lots of potatoes, go for it. If I like to smoke, I should be able to, too. If you want to open an all-vegitarian restruant, or one that serves rare steak, go for it. If I want to open a family dining room or a smoke-and-whiskey bar, I should have those choices, too. And you can either have the choice to patronize them or not, or you can have that choice taken away from you and made by someone else.
Some things are better for you than others. Some behaviors are riskier than others. Some things we don't have a choice about. But the point is that I don't need someone else, hundreds or thousands of miles away, making those decisions for me. First of all, most people, including most politicians, aren't nearly smart enough to entrust with that. Secondly, I haven't met anyone who thinks that kind of government fiat is a good idea that doesn't have an agenda. For example, the local smoking ordinance around here that was passed a year ago (and the state-level debate in Topeka) is a battle between two restrauant associations. One side represents family-oriented chains that wants to ban smoking entirely so that they don't have to accommodate smokers and to crimp the competition, versus a group of local bar and grill owners that wants to keep their businesses open. So...my rights are dependent upon their economic interests, and that's just flat wrong.
And it's wrong to debate other health issues based on economic interests, either. You want cheaper healthcare so you think you should be able to dictate my lifestyle, but don't think I should be able to dictate yours? Sure, you can ban French fries and cigarettes, as long as I can ban driving and skiing (we'll save >50,000 lives a year, and some of them are children!). Or, we can leave each other alone and leave government doing the few things it does well. I'm all for the latter.
I would be in hell if I had to eat some of the diets described here. You folks go for it, but leave me out of it and don't send your government thugs to force it on me. For any reason.