What about undigested food in his stomach? Did that also become one with the Force? It’s not really part of his body yet, so it should be left behind.
You’d think that vanishing into the Force was sucha clean and peaceful process, but it’s actually more messy than normal death.
When you think about it, Jar-Jar stepping in poop isn’t that out of place anymore, it actually has a long tradition dating back to the very first film: