One small note: Anything you ate before that didn't agree with you still won't. Surgery tightens up the leaking valve, but it doesn't "cure" sensitivities, intolerances, allergies or food triggers.
Example: I didn't tolerate anyting mentioned by the other posters except sweet potatoes, apple juice and sauce, chicken without seasoning except salt. But I have a sulfite sensitivity and didn't tolerate their foods before the surgery either.
A food processor for my chicken saved me from starvation. I had food put away in advance, frozen. I even took my own home-made chicken broth and pure apple juice to the hospital with me.
Don't even think about
a full meal. Just eat a tiny portion every hour or two. Your stomach is much smaller now and swollen. You'll get back to near enough normal in a few months. I took it as an opportunity to clean up my diet and eat healthier.