It takes a lot to stretch your tummy - eating large portions, many times a day, over a considerable period of time. If you’re sticking to your diet & your recommended portion size you can’t stretch your tummy. But I understand your concerns & your desire to be hyper vigilant. This is all very different to what you’ve ever experienced before & consequently you question many of your decisions & don’t want to mess up. We’ve all been there.
I remember taking it very slowly when I introduced new foods & cooked them very simply. My tummy had always been a bit fussy so I expected it to be more so after surgery. You’re fortunate you haven’t had any issues with nausea or being unwell. I had nausea from my multi vitamins & consequently had the foamies & vomited a few times but I found I could generally eat most foods. If something didn’t sit well one day, it usually was ok in a week or so. In the beginning it was often that the food tasted disgusting because my taste buds had changed not because the food itself upset me. It can be a lot of trial & error to begin so take the time you need.
I followed my plan pretty closely. I also asked my dietician about alternatives for foods I didn’t like or wanted to try. Honestly, I wasn’t hungry or all that interested in food but I kept to a routine of eating to ensure I got calories & nutrients in.
If you continue to stick to your plan, recommended portion sizes & meals per day, calorie goals (not every one has them) & meet your protein & fluid goals, you’ll be fine. When you get to more solid foods, your restriction will likely kick in if you eat too much or too quickly. It certainly helps keep you on track.
Good luck.