Hard..... more like challenging.  But certainly not impossible.  Just get into the habit of reading those nutrition labels and substituting stuff. 

Sugar = bad
High fructose corn syrup = really bad
bleached, enriched flour = really bad
enriched wheat flour = still bad
Coke = bad (although I occasionally indulge anyway)
Diet Coke = really bad
Crisco = disgustingly bad
Pam = bad
margarine = very, very bad!
red meat = not so much
pork = considering they eat, sleep, and play in their own crap, would you want to eat them?  Personally, I wouldn't.  And bacon is the most disgusting thing ever invented by man.

Okay, I think you guys get the point.  None of that is real food.  It's like only pretending to water your plant or feeding your cat cardboard and lint, somehow expecting it to still be happy, healthy, and frolicky.  Now for some viable substitutes:

honey = really good
fresh lemon = good
fresh oranges = good
whole wheat bread with no additives or preservatives = GOOD!
rye bread = good
all-natural, organic granola = really good
organic yogurt with 6-8 live active cultures = very, very good -- let's just say, GI problems B-gone!
tea = good
coffee (in moderation) = good
water = good
fruit juice (with no added sugar) = good
olive oil = a Godsend
real butter (in moderation) = okay, but still multitudes better than margarine
salmon = good
sardines (even in the can!) = good
Farmer's Market = YUM & Good at the same time !
wild game = again, yum
flaxseed = good
wild rice = good


Okay, well, you guys get the picture.  And not all this stuff is expensive, either.  Some of it may be, but it either goes on sale, or you can get it somewhere else for cheaper.  Sure, it may taste bland next to Americanized food, that has all the additives, fake flavorings, preservatives, and fake color, but your taste buds will wake up, and your body will be happier in the long run.   

And........  just say NO to cardboard!  *blech*