Hi adorable, welcome too healingwell!
I don't personally have a g-tube, and have never actually had one, as I find scandishakes very nice and easy too drink and get addicted too, plus i eat bucketloads of sugar.
I have a few friends though, who have all had very good experiances with over-night feeds. One of my friends finds that he gains weigth brilliantly on the feed, but if he tries too stop it, then he loses weight again.
I have heard reports also, that if you only have a poor appetite, because ou get full quick, it can stretch your stomach, so meals aren't as tough, and you can manage more in one sitting.
I hope it works for you, and that you can gain some weight.
Oh, and reading the rest of the post, it caught my attention. The reason being, is before CF patients were put on a high fat diet (before proper enzymes were invented, back in the 70's-80's I think). People were put on a zero fat, high protein diet. People managed to survive that. But I must say, looking back to then, a lot of kids with cf found there bodies couldn't cope on such a diet. I personally say-a good rounded diet, with lots of protein, and the right amount of enzymes too accomodate for any fat you have, and high-calorie- seems too work the best for me. I also have a LOT of sugar, and have developed a very sweet tooth, due to me finding it the best for gaining weight.