The rule of thumb for radiation is that the side effects begin soon after treatment ends. They then build up for about
3 years to what is called the "nadir" when they are at a maximum. They then begin to back off. This fits my experience.
If your sensitivity is due to the radiation treatments, you will be on a mild diet for a long time. I am - very little spices, no onions, garlic or hot peppers.

b 1950, 2012 PSA=11, 12/12 cores +. DVRP 12/27/12. 36 g, 35% PCa,EC ext., SV+,+ marg T3bX, G7(4+3). 2 week post-RP PSA=0.2, Firmagon ADT. Cont @ 3 mo, EBRT 70 Gy/40 ses. Last 6 mo. Eligard 10/14. 4/15 T=2.2, PSA<.02. 10/16 T=204, PSA=.08, 2/17 PSA=.13, 3/17 T=307 PSA=.19, 4/17 PSA=.21, 4/18 PSA=.65 6/18 PSA=1.15 8/18 PSA=1.15 11/18 PSA=1.58 1/19 PSA=1.67 3/19 PSA=2.12 8/19 PSA=2.9 10/19 PSA=3.3