We generate revenue from selling alcohol, moderate drinking doesn't end in hospitals being over loaded with infectious disease. We have also brought about standard tax rates for alcohol content
We have effectively banned smoking through pricing it out by over taxing it to change peoples behaviour. We have also further removed the freedom to smoke it almost every public space and indeed to sell them freely or advertise
The issue of weight is being addressed with sugar tax etc, but it is difficult to tax food (ie a necessity for life) without disadvantaging those who are the most needy in society. The shortening of life through carrying excessive weight may reduce the overall cost of that person in the Health service in the long run, who knows.