I think of myself as living a pretty healthy lifestyle, far from perfect but probably in the 90% percentile of Americans. But I just realized something about myself: I'm rarely willing to give something up, for health reasons alone, that brings me pleasure, but I'm perfectly willing to adopt new practices that might improve my health.
For example, take my diet. I eat very few processed foods -- stuff like packaged cookies and crackers, frozen meals, processed bread, even cereal -- partly because a lot of them make me sick, but also because, even when they're gluten-free, I genuinely don't enjoy them. So it's no chore to "give them up." If I want a cheap and quick meal, I'd much rather make a salad or some eggs. But then there's sugar. I know sugar is bad for you, but I get so much pleasure out of having a little sugar every day (always in my coffee, and usually a bit in some other form during the day, like a piece of candy) I'm unwilling to give it up. Same goes for alcohol, my only other real vice (unless you count rampant consumerism). A little alcohol is good for you, sure, but I regularly go past the one-glass-a-day required for added longevity. After being overweight, drinking regularly is the biggest single risk factor for breast cancer. But I get so much pleasure out of it, I'm unwilling to give it up. As for smoking and other drugs: I never had any desire to use them in the first place. So I can hardly be considered virtuous for abstaining.
On the other hand, I'll happily add new foods to my diet because I know they're good for me. I always buy the eggs with extra omega-3 now, and I try to buy some kind of super-green every week (as in kale and friends ... truth be told I think kale is a pain to prepare, but John loves it). I started taking vitamin D in the morning because I read that's when you get the most benefit out of it and that it helps you sleep. I even tried doing the standing-desk thing for a while, though I fell out of the habit when I changed desk setups. All in all, adding on seems like a better bet -- if it works, great, and if it doesn't, it didn't actually detract from my life in any significant way. (If it did, I'd stop doing it.) But when you give up things you love, you run the chance of dying young anyway. And what's the point of living to 100 if you're not having a good time?
I guess another way of saying this is, I'm pretty good at forming new habits, but bad at breaking old ones.