Not the fat smokers.
All of us will get ill and die eventually. Something will get us in the end and towards the end we are very likely to need some medical attention.
Those who are ill young may cost a lot in the short-term with cancer treatment or through diabetes etc but people who live an extra 30 years and then still need at the same (or more) treatment and care will surely cost more over their lifetime.
I might even argue that dying young and suddenly from say, heart attack does the NHS a favour. Caveat, I'm not being entirely serious but offering an alternative view to the one doing the rounds here ATM.