biliary dyskinesia and marathon swimming nutrition

Hi folks,
Interested in talking to anyone who has had trouble with gall bladder issues, and specifically biliary dyskinesia--which is low motility of the gall bladder without stones of any kind. I was diagnosed in the fall, after on and off pain for quite some time, finally resulting in a trip to the ER which started the diagnostic process.
My gall bladder motility is terrible, around 13%, but I am doing everything to not have it removed since that doesn't necessarily resolve this issue. I am a really healthy eater and typical risk factors (eating a lot of fried foods, obesity, and a sedentary lifestyle) are not applicable in my case.
My issue is that I am advised to have a very low fat diet, and also avoid lots of meat, as well as empty carbs. Also not supposed to have a lot of things like beans, etc.
I was doing most of these things already, but right now, I am struggling with meeting my caloric needs as I ramp up my training for the season. (I wasn't diagnosed until after last season ended so I was still eating things like peanut butter regularly.)
I think this diagnosis may also account for why I have had trouble with many feeding options (carbopro, etc.) and am interested in hearing what anyone with this might be doing for their feedings.
Anyone else have this issue? And if so, how do you handle your swim nutrition? Planning another long one for this summer and want to start experimenting now.
Thanks everyone!