Can the government dictate what people can buy?

Have you see this commercial? ... http://youtu.be/XV6GX8qwfqs

I've caught it a few times over the last month or so, and while I would certainly take issue with the government telling me what to buy. That being said, if the government is giving money to individuals and families across America via various entitlement programs, don't they have the right to stipulate what can and can not be purchased with that money? Cigarettes kill people. Increased caloric intake due to sugary drinks leads to diabetes and obesity (among other variables, I know).

I lived in Chester, PA for nearly 10 years, one of the most economically disadvantaged areas of Pennsylvania. A city, that to the best of my knowledge, still does NOT have a grocery store to call their own. I used to do my shopping in neighboring Eddystone, where I would see folks purchase very unhealthy foods and drinks, and on the way out of the store, throw a $20 into the automated lottery machine. iiWii, we all have the right to play the lottery, and buy things we want--but at the same time, I think government has the right to reform entitlements to ensure the funding being provided is used to the best of it's ability.

Look forward to your thoughts.