@lifutang Did your SpaceOAR placement proceed on schedule (on May 23)? You asked in particular advise about which foods and fruits are gas-producing and should be avoided"during treatment." You received helpful responses for "during treatment." Tangentially, there were also comments about foods to avoid before/after treatment.
I noted that there were some in our group who were not advised on foods to avoid before and after radiation, or even during treatment.
I was advised March 26th (start of my ADT-Orgovyx) on what to avoid prior to my first treatment on April 9. You were injected Eligard on March 18, and not told "about foods to avoid issues" until the end of April, at which time you received a guidance about foods to avoid. Therefore you'll be on diet for about 5 weeks prior to your treatment beginning in early June, longer than my 2-week pre-radiation diet restriction.
I would like to address the post-treatment diet restriction. @daveinflorida was on track to finish his 28-dose radiation as of mid-May and was hopeful that maybe by then he could be back to a normal diet. I look forward to hearing Dave's update, as I would want to compare notes with him.
My wife and I went on a cruise on week 4 after my last SBRT. I mostly observed my diet restriction as advised by my pharmacist and oncologist, but by the second to the last day of the cruise, I started tasting a bit of the foods that I avoided until then (though scraping the outside of the meat for example, to remove some of the spices but inside still tasted spicy). I am continuing my "experimentation" a little at a time at home, but I am not yet at my full pre-treatment diet (still no fried foods, caffeinated drinks, salads/uncooked veggies). I'm encouraged by @jeffmarc 's experience of never "before-during-after" salvage radiation was he advised to avoid certain foods [though he had cut back on some that he believed aren't good for him (unrelated to ADT)], and @heavyphil 's assurance that "dietary restrictions are ONLY for radiation. Once completed, you can eat anything you like!" Echoed by @northoftheborder .
Ultimately, we each individually will how much liberty we'ill exercise in what we eat post-radiation/while still on ADT; our individual tolerances vary person-to-person. The closest material I found so far regarding "after SBRT treatment" is shown below, with the caveat that "AI responses may include mistakes." But this is not yet a concern for you until probably mid-July when your 28-fraction treatment ends. I wish you the best! - Vir