You cannot possibly eat gluten without eating something that is processed, period. Every food that contains gluten had to be manufactured from gluten-grains and other ingredients into its final form.
I always tell people that it’s actually very simple to eat a gluten-free diet… if you only eat meat, fruit, vegetables and legumes.
You could even eat some grains, such as rice. While processed, rice in its purest possible form can’t possibly contain any gluten.
The only chance you have of accidentally eating gluten is if you eat anything processed.
This unfortunately includes most restauarant food. Most of it is made from processed ingredients, and you don’t have control over its preparation. Obviously, following the above advice isn’t so easy if you go to a restaurant. You have to make adjustments and do some planning.
But if preparing food at home, and you know how to cook, you don’t have much of an excuse.
Even price is not a concern: Processed food is more expensive per pound, per calorie, than whole food from the produce/meat aisles in their purest available form.
If you need to follow a gluten-free diet, and you’re struggling to maintain it, you may find adherence a lot easier if you go clean and stick to meat, fruit, vegetables, and legumes.
(And of course if you’re vegan, you won’t eat meat. But the other three categories should cover your nutrition needs well. If vegan, I would make sure to include rice.)