In a nutshell, people with CF misprocess fats, wind up excessively acid and wind up with serious malnutrition. I got very picky about the fats I consume, aggressively addressed the nutrient deficiencies until my body worked more normally, and I eat a diet that compensates for my body's tendency to become way too acid.

I also avoid chemicals that bother me, avoid exposure to germs, etc.

I look fairly ordinary these days. It isn't obvious to other people that my entire life revolves around this. It is sort of like being a kosher Jew who eats only approved foods and so forth.