Earlier quoted context omitted.
Isn't this a given though...? Exercise and eating right will improve outcomes no matter what genetics you have.
What if you don't like exercise and like to eat? A lifetime of forcing oneself to do something unappealing and then topping it off with denial of things one likes doesn't sound like a overall good trade, even if you live longer.
That's me in a nutshell. There are lots of ways to get exercise without "exercising". Personally I tend to get off the bus a few stops early each morning and walk the last 30 minutes to work. Great way to some exercise in and a great way to start the morning. Another example, my closest food store is 1.5 km down the road. If I know I only need a few things I'll walk instead of taking the car.
On the food front I eat most of what I used to eat but less, compensating with getting higher quality products. I also started to get much more adventurous with my eating trying all kinds of different ingredients and cooking techniques, not because they where healthy, but for the love of food. It turned out that some of those things that where pretty delicious also had the side benefit of apparently being healthy as well (who knew). So I slowly started to phase those things more into my diet. Over the course of a handful of years I managed to greatly improve my diet without feeling like I was giving up on anything or denying myself anything I wanted.