It will make certain diseases more likely- sure but, they can take time to kill. As an example, years ago, I thought I was having a heart attack. Excruciating pain in the chest. But, I felt ready to die so, didn't phone for an ambulance. It eventually passed but I got further attacks. Turned out it was gallstones. Eventually, the pain wouldn't go for 2-3 days and I couldn't stand it anymore. A stone had moved into the bile duct. Gone untreated, maybe that would have killed me in the end but, the not knowing if, when or how much pain you'll have to endure makes it a difficult 'method' to do. I so desperately wanted to get out of pain, that I sought help. I suppose at that point, I could have asked them to treat the pain but, leave the problem but, I'm not sure they would have been willing to do that.
My diet has been pretty poor of late and I've shirked exercising so, I've put on weight and I'm so unfit. Consequently, work is so much harder so, I'm all the more miserable.
I think it will depend if you can get benefits too, or financially sustain yourself some other way or, be willing to go homeless to do this. Otherwise, it can make a fairly long, drawn out life all the harder to sustain.
I'm realising the opposite. That I'm going to have to make an effort to start taking better care of myself soon. Otherwise, I'm going to suffer a whole lot more before I die. I'm feeling characteristically resentful that, either way I'll suffer. I don't enjoy healthy things.