In a society where government is not participating in helping people with their health care, what moral right does it have to make "unhealthy" things illegal?

The government does help (to the tune of trillions of dollars per year) with their health care.

Medicare and Medicaid represent the largest segments of U.S. federal health spending, consuming over a trillion dollars each. Medicare accounts for 21% of national healthcare expenditures. Medicaid constitutes $1 of every $5 spent on healthcare. The US government is helping the poor and the old with their healthcare