I think corn is one of the worse starches around, especially when it's processed a lot, such as in pasta. Again, gluten-free is not starch free. Gluten is not a starch. If you are eating any bread or pasta, then you are probably not going low-starch. You need to avoid all grains (corn is a grain), potatoes, bananas, puddings, and anything with starch added (which includes most processed foods).
Yes, it sounds like a lot of trouble, but it's worth the real effort to have pain levels greatly reduced. I went from getting ready to apply for disability, due to the pain, to now functioning quite normally with only an Aleve each day.
AS symptoms started 1991. Official dx in 2006 with HLA-B27+, fused SIJ, bone spurs in back, extreme rib/hip pain, and other family with SpA. Started Enbrel in 2006 with good results, but stopped in 2010 due to nerve damage (MS) from it. Now getting good results with no-starch diet.