We're all terminal, no one is getting out of here alive. I don't fret much anymore. It is my desire not to buy any food that has a label (ie. prepared, boxed foods, cereals, mixes, etc), but in reality, life often gets in the way. Life is just too busy and complicated (and expensive!) for most of us to do what we would like to. So, I compromise. I often buy convenience over conviction. Sometimes, when we've both been going all day we buy fast food instead of coming home and making a meal. I know it's not the healthiest we could do, but "it is, what it is."
One thing that gives me hope is that there is a lot of information out there, and I believe a lot of it is just hype. My Grand dad was overweight, smoked a pipe, ate bacon or sausage with his eggs every morning, put gravy on everything, loved snack cakes, and he still lived to 90 and was healthy until the end. My Grandmother on my Dad's side was never overweight, but she smoked cigarettes, ate a lot of fast food and box mixes, etc. and she lived on her own until she was 90. It was only after she fell that she had to be moved into a personal care facility. She lived there another 5 years.
On the other hand, I've also known a lot of people that appeared to be healthy, that have passed at such young ages. Seems to be "luck of the draw" to me... maybe not, I don't know. Anyway, if you can avoid the junk in the stores, more power to you. You'll definitely be better for it. But I just don't see any major changes in my life at this point.