I asked my husband if he had problems with eating and digesting when he was younger and he said it's kind of a catch 22. He remembers being really hungry and wanting to eat, but then when he did eat his stomach would go into knots and hurt so bad and he would keep having to go to the bathroom. So you could be right on with that thought Sharon.
One question I have, (please keep in mind I don't have a little CFer so I may be way off here) but are your kids getting solid foods for every meal and every snack? My husband has found that sometimes it helps his stomach (he has DF508, with digestive issues) to not eat so much solid food and supplement with protein shakes. He will still usually have 3 solid meals a day, but for his first meal of the day he will have a protein shake/drink to start his system off clean. Once he starts moving around for the day he will have a meal with some solid food (sandwich, burger or whatever) then for his next snack he will have 2 or 3 boost shakes. He'll have solid food a little after 1 or2 pm (sandwich, burger, stroganoff, whatever is in the fridge or if he feels like cooking). Then he'll have another protein shake and sometimes some soft food. Then dinner is always a meal, but any snacks after dinner time are soft foods like icecream, boost plus shake, or protein shake (if he is that hungry). He says this helps him so his system doesn't get so backed up. Even with the enzymes (and in his 24 years he has tried every brand that is out there) there is still some pain and back up and excessive bathroom use.
I don't know what the thought and research is on kids and proteins shakes (what the long term effects might be). I know pediasure makes supplemental shakes, and the makers of the enzyme Creon make a nestle brand protein/supplement shake that can be used by kids, and Ultrase also makes the Scandi shakes. I might be something worth looking into if the stomach pains and lack of appetite continue to be a problem. The supplements from the above mentioned pharmaceutical companies are free to patients who use their enzymes. Can't hurt to try something for free. I have some scandi shakes that my husband doesn't use (he prefers the boost) if you would like I can mail them to you.
Julie (wife to Mark 24 w/CF)