It’s really don’t match symptoms to colon cancer, yellow stools are fine actually, but don’t know about it being oily, sound like something not quite right in the digestion department, I know problems with the pancreas can give fatty stools that can be hard to floss out. And also now that you mention being obese, diabetes can cause a loose stomach as well, but there should probably be more symptoms like extreme thirst. And it may be something like lactose intolerance or other food allergies.
I don’t think anything is wrong with you so try to eat healthy and take some extra fiber pills to get the stomach back on track. And of course do the test the doctor gave you!
I know you said that diet doesn’t change you bowl movement, but one health week isn’t enough to change it for the better. It may not work, but try for some months.
2017: 15mm Tubulovillous adenoma- Low grade dysplasi.
Next scopy: original 2020 probably 2018-19