(Furthermore...)
--The following is a bit rigorous, and dramatic, but it is so to make a point. So, don’t critique it without this consideration…--
Think about it. We don’t have the natural digestive benefits of pancreatic enzymes. So we should be eating food that is rich with its own biodegradable enzymes (all natural food), not food made in an industrial warehouse with the synthesized chemicals, some basic like C-6 H-12 O-6, and others far less reasonable, like MSG, sulfides, disodiumoxide, or ferrous sulfate, etc. There is a reason why sugar isn’t a powder or grain you find growing in the earth like salt. Even sweet sap from trees (syrup) is rich with natural and nutritional elements before it distilled in to an industrial syrup. Again, I know this is very hard core, or “granola”, and that few can eat a processed free food diet in today’s modern world, but it clearly is what is best for everyone, us in particular. And a balanced diet is the way to go, but “balanced” with different nutritional benefits not balanced as in a little crap food with a little healthy food, e.g., balanced with a meat, vegetable, fruit, or grain, not balanced by eating a bowl of Frosted Flakes with berries, or a nice turkey sandwich with Cheetos and Oreos, and a soda to wash it down.
As for fat, fat is tough for CFers to digest. You don’t have to eat fat to get fat. Fat in its typical form is a LCT or Long chain triglyceride. Digesting too much fat is taxing on the liver and gall bladder, if you have one (I don't have a gall bladder because I ate, as the dietician prescribed, anything I could get my hands on, particularly fatty foods). The natural fats that exist in the world exist in only a small percentage of the food. Ask yourself, what percentage of a nut is pure fat? What percentage of fish (salmon even) is pure fat? What percentage of a free ranging animal if fat? Very little. We humans are not designed to consume the amount of fat we do. So why would someone who has a challenged digestive system, and has particular trouble digesting fat like a CF patient, consume an inordinate amount of fat in his/her diet? To get fat? You can just as easily, if not more easily put fat on you body by eating a raw sweet potato, baked potato, or even oatmeal immediately after drinking a healthy juice. The juice jacks up your insulin levels, and the carbohydrates from the potato or oat is easily converted to fat. The only benefit of eating straight fat, or having it in your diet, is that it is the most easily form of food convertible to energy (ATP, Adenosine Triphosphate). ENERGY! It is good to consume for immediate fuel, not to consume for storage. Again if you are going to consume for storage there are plenty of other food items one can consume with greater nutritional benefit and are less taxing on the digestive tract.
Also, there exists a functional relationship between the liver and the lungs. If the liver experiences problems, it is likely the lungs will be affected in some fashion, at some level. While most of you consume excessive fat to gain weight in the form of milk, pizzas, or chips, you are taxing your liver and complicating your lungs with systemic inflammation responses.
Fat is also not found in the environment, ripe for harvest. It found in food, coupled with natural enzymes and complex nutrients. Fat is found in raw meat, raw nuts, and raw vegetables for a reason. The way we mostly encounter fat is as an additive to make food taste richer.
Look I eat crap (usually Hostess Chocodiles or a bowl of super crap cereal) very occasionally, and I pay for it when I do, so I learn to eat less and less of it. I can’t eat the exact diet I recommend every single day, it is just too tough, expensive and time consuming. But I strive to improve towards the ideal I mention, and as I get closer to perfecting my diet, I manage to reduce the challenges I am posed digestively with my CF. The older you get the more you will come to meticulously identify what you consume as being good for your health or bad for your health. And if age doesn’t inspire you to adhere to a strong truly healthy diet, unfortunately, poor and poorer health will.
I am 33 with CF, and have a M.S. in Environmental Biology and a B.A. in Nutritional Sciences. My weight also fluctuates between 135 and 145lbs when I am healthy. When I am sick it has dropped as low as 114. The heaviest I was ever able to get was 163 lbs. But to attain that weight was a very expensive and time consuming process. So, I feel I know what I am talking about. And yes, I have required a G-tube. …once.