The seatbelt laws aren't to protect the person wearing the seatbelt. They protect the other driver. Imagine for a moment you are in an accident. It is entirely your fault. The other driver wasn't wearing their seatbelt and is hurt badly. Perhaps if they had been wearing it, they would be fine. But they weren't. Now you are liable for their medical care. This is hardly fair. One of the principles of our legal system is that people are not responsible for things beyond their control, and you are certainly not in control of whether or not Joe Blow wears his seatbelt. Enter the seatbelt law. Now, you have the accident, and the guy's not wearing his seatbelt. Oh well, poor him. You aren't liable anymore. Your insurance company rightly denies him payment because he wasn't wearing his seatbelt. The same holds true for cyclists. If you hit an un-helmeted cyclist and they sustain a head injury, you're off the hook.
Now, of course, banning trans-fats is a different issue all together. First off, trans-fats, unlike car accidents, are not fatal in single doses. Second, no one is forcing you to eat trans-fats. It's not like that sports car that ran a red light and t-boned you; no waiters are running around stuffing big macs down people's throats against their will. Third, it's just dumb.
However, the government does have the right to regulate the sale of food stuffs. But they also need some perspective. The problem isn't that people eat trans-fat, it's that they eat way to much of it. And it's in everything. And we need it. It's like telling people they can't eat protein. You need fat, of all varieties, to be healthy. You can't cut out an entire nutrient category.
The problem in America is that never before has a people had such access to calories. Finding enough to eat has been the premier struggle for man kind since we first threw rocks at wildebeest. Now the premier struggle is deciding to watch CBS or NBC. American's are fat because we're too damn successful. If we were barely making it like the people in third world countries, yeah, we'd be skinny too. (And no, Europe, you aren't nearly as successful as us - and you got fat people too. So stuff it.)
They should just require clearer posting of nutritional content. You can get the info at fast food places now. If you ask for it. By mail.