Depends on the habit.

It didn't do much for cigarettes in the USA. I watched the price go from $0.50 per pack to over $4.00 per pack. The only thing that made a difference was making it illegal to smoke indoors, to protect neighbors from second-hand smoke.

IMO giving the government the ability to choose what is a good food and what is a junk food is also a bad idea.

The vegan lobby gets in there and decided that meat is a fattening food, and before you know it, there's a tax on meat.

Same for fat. And we know the sugar/starch lobby keeps telling us fat is what is making us fat, even though we got obese on a low-fat diet.

Just thinking out loud here: If you want the people to be thinner, put a tax on health care for obese people. The fatter you are, the higher your copay is. After, all, fat people cost the health care system more, and for most of us, being fat is preventable.

I'm sure there are reasons against this, too.