While I was a kid I used to drink soda for dinner every day, I only quit when I was like 15-16 or so. I've also been very sedentary from about 12-20 (I'm in very early 20s), mostly walking to and fro school. I spend much time infront of my computers, seems like my vision got worse due to this. I'm very thin and underweigh, I don't think I eat enough meat and I tend to eat a lot of white bread. I don't do things like drugs, smoking, alcohol, but surely all of this must add up to reducing my lifespan by eroding veins, internal organs, telomers etc? I wonder how bad it must be at this point, and how much time I've lost, and how much of it is reversible. I also know one gets new cells every 7 years, so would one of the year one gets new cells be a good time to start living more healthily? I assume how one lives in the periode before the old cells are replaced determines how good the new cells will be, "sets the standard" so to say, and thus that would stick with you for the next 7 years, yes? I don't know the details of the "getting new cells" process, whether it happens slowly over the last year of those 7, if it happens in the few final weeks or few final months.