Can I walk the Camino gluten-free or as a vegetarian?
If you are a vegetarian, pescatarian, vegan or someone with other dietary needs, you are quite familiar with the extra effort it takes to eat out. On the one hand, the Camino could be considered more difficult, as we are usually in smaller towns and there aren't the choices you find in a big city. But on the other hand, the restaurants along the Camino are quite used to catering to a large number of people from all over the world with all sorts of dietary preferences or restrictions.
In short: You are not alone.
We certainly have had many people with special dietary needs on our trips and I'm 100% sure they would all tell you that we fully catered to their needs. It's what we do: We make sure everyone has what they need.
Breakfasts are a buffet, offering you a choice.
Lunches are generally offered as a picnic. We go to the supermarket daily to shop. Spanish and Portuguese supermarkets each have a natural foods section featuring, among other things, a gluten-free selection of products. We can pick up anything you request and keep you stocked for other times of the day, as well.
For dinner, we're normally ordering off the menu, which gives you a good number of choices (rather than just having a few things on a fixed menu). And knowing your needs, we'll be in communication with the restaurant in advance to ensure you have something available that is suitable. We are not eating in Michelin-star restaurants, but the places where we dine are generally upscale. This means, in our experience, that the chef is more than willing to cater to special requests, and they seem to rise to the occasion quite well. Perhaps it is because you've given them the opportunity to be creative.
One nice thing in Spain (and across the EU) is that a new coding system is used to tell people about what allergens are found in each dish on the menu. The list is printed once on the menu and then each menu item refers to it by numbers in brackets. Here is the standard list:
Cereals containing gluten (wheat, rye, barley, oats, spelt, kamut)
Crustaceans (e.g., shrimp, crab, lobster)
Eggs
Fish
Peanuts
Soybeans
Milk/Dairy products (a very common one)
Nuts (almonds, hazelnuts, walnuts, etc.)
Celery
Mustard
Sesame seeds
Sulphur dioxide and sulphites
Lupin
Mollusks (e.g., clams, mussels, squid)
Don't expect to find this in little cafes all the time, but the type of restaurants we frequent should all have this.
By the way, here is a good rundown of all the terms and categories you'll find on a Spanish menu.
So I wouldn't be too worried about diet in Spain and Portugal, at least not in the places along the Camino. There are exceptions, but fortunately they are relatively rare.