One of my coworkers has had several operations in her digestive system during the span of a few years. She isnít slim at all so I donít know if there is always a correlation between serious digestive issues and weight. OTOH Kateís weight might be related to long term issues we havenít known about before (which is totally fair IMO).
If you're resecting any intestines the post op can be a couple weeks. Nothing to do with weight, health, or age. It can be standard depending on the procedure and risk of infection.
Kate has been stable at this weight for decades now, her family and William all put value on staying physically fit and active. People comparing her to her 18/19yo body with a tiny bit of more weight on it while in college is just a bad comparison.