Have had gastroparesis for years (no other lower colon issues). I've been vegan for years & in good health. But the awful symptoms create such bad stomach gas/bloating that it keeps me awake nearly thru the night (sometimes til dawn). Repeated doses of charcoal used to help (& simethicone gells don't touch it), but now not much. Kaiser has done a few endoscopies & found no irregularities there. Even 2 stomach emptying tests that their gastro doc came back normal (which is BS, because if they'd done the test in the PM they'd have concluded differently; also, their test is brief while the gold standard for stomach emptying is a few hours long). Seen all manner of western & alternative health providers. Finally an ND had me do a SIBO test (about time!) & they found abnormally high levels of methane, which is created by bacteria. The slow stomach motility means foos sits longer, ferments & can host the bacteria, this creating the gas. Presence of the bacteria can affect stomach/upper digestive motility. So I did a round of specific antibiotic, though it's not helped. I'm now working with a good nutritionist who utilized the FODMap process to eliminate certain foods for a limited amount of time to see if my symptoms reduce. It's NOT an easy diet (2 phases, totally lasting 6 weeks). Just make sure your primary doctor takes the SIBO test results seriously & has a plan of action for you If you have a sweet tooth, that'll have to mostly end). There ARE some supplements out there that can help motility issues. Iberogast (by Bayer) has been effective for some (although not me); but it's only available on-line via Canada; do NOT allow the order to come from anywhere in eastern Europe. And a good ND or nutritionist who knows the chemical balance of foods & alternative herbal methods has some great ideas for supplements that can stimulate the Vagas nerve, which is what drives stomach motility. If your nutritionist or western doc doesn't support or know about any of this stuff, find someone who does. Finally, reducing stress & distracting your daily challenges with this disease are critical.
By the way, did you develop any good trick to reduce the gas when it just keeps coming back all night? Besides the diet, I drink 3 cups of unsweetened ginger tea daily. Good luck.