@KarenNWendyn - it starts with Gastroparesis and
@blitzc that feeling full is probably due to this - the stomach takes longer to empty. This is usually followed by a slowing in peristalsis. Now if you think about it, digestion starts with salivating at the idea of a yummy meal you can smell, and this starts you swallowing a bit more and you get your system ramped up for the meal and peristalsis has already started and everything is moving in the right direction before your first bite. Remember how hungry you could get in a restaurant smelling meals and seeing people eat because peristalsis would get your stomach and upper small intestines emptied right out in anticipation of new food.
When you combine being more sedentary due to limb involvement, with no stimulus of the smell of your food cooking, and if you have been eating a bit less and less before getting the peg, these all seem to combine to slow the digestive tract right down. Dehydration will slow things down too.
People who blend their own real food at the time the family eats often digest better simply for this one factor alone. Sometimes peg fed people find the opposite if they receive formula and find the smell of the family meal cooking makes them feel nauseous - often because they still have residual formula that has been sitting in the stomach some time and it still doesn't empty in repsonse.
Then the great question about the respiratory involvement - yes. As the diaphragm weakens, anything that puts pressure on it is going to be really noticed and so we find that position (eg laying down flat) and having a full stomach both mean the diaphragm has more resistance to work against and if it is weakening, then this causes you to start to feel a bit off, woozy, distanced, and you feel more full because of the breathing involvement ... kind of vicious circle you see?
So two great strategies are - bipap and pump feeding. Some elect to pump feed slowly overnight, then they can just top up, or if still eating a little can have absolute favourite little snacks for pure enjoyment through the day. Through the day you will then not have the heavy feelings, and your breathing will be freer with the stomach not being full so your quality of life can go up significantly.