A nanny state is the result of society reaching a point where an individuals actions effects everyone else. This could be caused by laws, excessive population, natural resource depletion, etc.
Alcohol, tobacco, drug use and obesity. These are all unhealthy activities where the government has passed laws limiting personal responsibility to the point where those actions effect everyone else. The government will not let people die from their actions.
Rather society steps in and pays the cost to fix these people. But of course the cost is actually paid by healthy people in the form of higher taxes and increased health insurance premiums.
So the government is trying to be fair to the rest of us by making laws to reduce these behaviors. It is sticking it’s nose into peoples personal behaviors because their actions are costing the rest of us money.
The solution to the nanny state would be to make people pay the full price of their unhealthy choices and stop spreading the cost to the rest of us.
But of course that wouldn’t be “civilized”.