I walked the Camino last year from Pamplona and being gluten free was a challenge, but got easier as my comfort levels and experience with how manage my diet grew. My Celiac is so pronounced that even eating food that has touched bread can leave me in agony for a week or more. This is not a lifestyle choice, or something we can just choose to ignore.
As someone already mentioned, there is a growing awareness in Spain around Celiac disease and gluten issues in general. The best advice I can give you is always err on the side of caution and carry as much food with you during the day as possible. Learn the phrases 'Sin Gluten', 'Sin Pan', 'Soy alérgico'. My spanish is terrible, but I was able to get across what I meant.
Every evening my girlfriend and I would shop for the food we would carry with us to eat the next day. We were careful, but ate extremely well on the Camino.
Our typical daily diet included:
- fresh fruit, we carried 2 oranges, 2 bananas and usually either peaches or plums
- nuts
- yogurt
- a block of cheese. sometimes we would get the presliced cheese just for easy access while travelling
- ham, packages of ham (always look for the 'Sin Gluten' label). We alternated different kinds of ham to not burn out on any one
- cans of fish/seafood. tuna, mussels, pulpo
- rice cakes and jam
- chocolate
In the cafes we stopped at during each morning of walking we would look for the potato tortilla. Oh, and Magnum ice cream bars have a few varieties that are gluten free, and their poster ad in stores labels which ones are Sin Gluten.
Really though, shopping each night in a market and carrying the next days food with us was the best thing we did to keep me safe.
Remember that calories are precious commodities on the Camino and staying healthy is not really a choice. It took us a week or so to really get the rhythm down.
Even as well as we ate, there were welcome surprises along the way. One albergue/hostal outside of Palas de Rei had gluten free buns for hamburgers. I thought I was going to cry for joy.
Anyway, please feel free to ping me for more details/specifics on what we ate, where we found things, etc. Finding Gluten Free food was probably my biggest fear before setting foot on the Way, but it all worked out. I'd be happy to share more of that knowledge with you, or anyone else.