My only evidence is anecdotal. I know several people who buy gluten free because they think it is better for them, not because they have a medical need. There is a lot of money being spent on marketing "free from" products and supermarkets are not known for doing things out of the goodness of their hearts. I wasn't actually objecting to the "free from" section just envious there wasn't some shelves with the various low carb substitute products grouped together. Obviously there are the naturally low carb products like vegetables, meat, fish, some fruits ( berries) salad ingredients, cream, cheese and pork scratchings that you mention. I may be wrong but I think these are also gluten free. I admit I didn't realise that "free from" catered for all these other "allergies". I have just looked a items that might interest me like bread and found that it was high carb, and 3 times the price and walked away disappointed.