Let's raise taxes on sodas so less people will drink them.

This is America.  As long as you aren't harming anyone, you should be able to do what you want to do. Right? If you want to wear your hair very long and never wash it, you should be able to do so. Right? If you want to eat potato chips for breakfast, lunch, and dinner, you can do that. Right? If you want to smoke two packs of cigarettes each day, that's okay. Right?

What if your neighbor does these things? Long hair? No problem. Eat potato chips? No problem. Smoke? Now hold on. That's bad for them. They shouldn't do that. It will kill them. So let's raise taxes on cigarettes so it will be more difficult for them and we'll save their life!

That's the mindset of many people including politicians who have the power to increase taxes on 'sin products' like cigarettes, alcohol, and soft drinks.

Sin Tax (Wikipedia)
A Tax to Combat America’s Sugary Diet (New York Times)

Time to crack down on Big Tobacco (CNN)

There are many instances of people deciding something isn't good or good for people and attempt to get it outlawed or taxed.  These include same-sex marriage, smoking, abortion, stem-cell research, sugary drinks, and many more.  It's not enough that these people don't do it themselves.  They want to impose their beliefs on someone else.  As long as they aren't hurting anyone, leave them alone.  If they want to hurt themselves, that's their choice.  As a side note, smokers who do so with kids in the car should be liable, but that's another blog topic.

The most infamous attempt to regulate behaviour was Prohibition which caused large-scale bootlegging and a thriving black market.

Here is one current attempt to forestall sugary drinks that failed.  Failure of State Soda Tax Plan Reflects Power of an Antitax Message (New York Times)

UPDATE: The upside of raising taxes on alcohol - fewer deaths, researchers say (LA Times)

UPDATE - More than just the United States: Minimum pricing alcohol plan facing defeat (BBC News)