Just a few thoughts . . . the digestive tract works by squeezing the food as it passes along. This is probably helped by us walking, running and generally just bending about all day. As the food goes in at the top and comes out the bottom (excuse the pun) then gravity must play a part in the movement. So yes, I'd saw that unfortunately, not being on you feet all day will have a detrimental affect on your speed and efficiency of digestion.

There are undoubtedly foods that cause bloated bellies more than others, mostly carbs, so it makes good sense to experiment to see how each food affects you and try to avoid or limit them.

Also, I'm not sure that the slower speed of digestion will increase the likelihood of the food turning to fat. More like the opposite, I'd have thought.

I have a German Shepherd whose pancreas doesn't work and who needs powdered enzymes with every meal. Stay with me here . . . we found, after many months of experimenting, that giving him four smaller meals every day, rather than one or two much bigger meals helped him gain and keep weight. Also his stools were much better. The point I'm making is that giving his digestive system a chance to digest smaller amounts at any one time it helped.

Not quite sure quite how this translates into your problem, but, possibly, by eating smaller amounts your digestive system won't be so overwhelmed and it can digest your food more thoroughly and therefore, hopefully, eliminate some of the bloated feeling as well as squeeze out as much of the nutrients as possible.

Just some food for thought and this time no pun intended.