As a side note if you did just get fat and smoke you wouldn't be a drain on the NHS because being fat and smoking disqualifies you from many procedures and you are likely to die right around retirement age, after you paid most of your lifetime taxes but before you start consuming the very expensive age-related healthcare.

Ironically it is the unhealthy that are overpaying and the very healthy who are underpaying because age related care is such a huge proportion of lifetime medical costs, and that is still before adding in potential sin taxes paid.