I have been thinking a bit about authenticity and allergies and how they play together, namely in an SCA environment. Some who know me, know I dislike making any substitutions whenever it is possible to provide the proper ingredient, or when I do that there had better be a decent reason and that the substitution is the most appropriate one for the recipe.
The biggest obstacle that has come of late are the growing number of people requiring a gluten free diet where a medieval kitchen really isn't designed to be free of all these gluten containing cereals. Now, obviously, it is not difficult to find recipes that contain gluten free items without compromise, the dietary charts I made from a few example cookery books shows this (and I believe are still up on this blog from the top menu, if not, my website at least). The compromise comes when preparing a number of feasts that actually could have been served within their time period, such as a dinner that could have been prepared in 1531, somewhere in Spain (yes, I'm being a bit vague) as opposed to a feast that encompasses dishes that may have been served at various meals in various places somewhere within the limits of the SCA timeline. Obviously the latter would be much easier to do without compromises to the individual dishes and far more difficult to achieve without compromise to the entire feast, unless we were just looking to re-create a smaller/private meal.
Gluten is not the only issue we have though, but thankfully we can happily not worry about the more common peanut allergies or any new world food allergies (unless we were making some very strange substitutions). There are an innumerable amount of dietary issues that many SCA cooks meet and I'm not going to make any bones about it, it can be tough for anyone to deal with this because not only are some cooks trying hard to provide a more authentic eating experience for those in our medieval/renaissance club, but can also be untrained cooks or working with untrained staff, people walking in and out of kitchens (I don't have to explain the problems that can come from this to most), working in very unfamiliar kitchens and a myriad of other things that can occur in the process of creating a meal for 20 to 200 people. For someone used to cooking for their dietary needs, this might not sound as impossible (though under the circumstances, things can still get out of control), but for someone dealing with several different needs and not necessarily their own, the odds increase towards the negative.
For some examples of what any cook can expect, here is a list, and likely not a complete one, of some food issues I've come across. (note: I say "food issue" but it's not meant to offend or imply the importance is lesser, it's a catch all for allergies, food intolerance, religious needs and dietary choices, all of which is a very serious matter).
allergies covering period foods
-fish and/or shellfish
On top of this, I've found people with corn and other grain allergies which are used in alternative mixes for people with gluten allergies. Because of this, I find it's actually better to just not substitute and pick a recipe that just doesn't have it.
Besides allergies and food intolerance, I had to deal with other important dietary needs that excluded:
-meat, and meat products, in general
-...and various combinations
It brings to mind, "The Man, the Boy, and the Donkey", try and try as you might, you can't please everyone, there is no solution beyond what people can do for themselves.
We can not please one person and be fair without attempting to try and please everyone but on looking at the list above, and I have seen more than 3 of these needs at the same meal, the reality comes down quickly.
A well thought out meal of many cultures and areas is going to have at least two of these food items in it and some not in a small part. There is a degree of authenticity that we would have to give up in some cases, this beyond the amount of authenticity we give up normally with modern versions of food items and in some of it's preparation with our modern equipment and methods.
My preference for a meal is to provide enough variety using different ingredients so that most people can have enough of at least a few items each from a menu and to have enough at once not to be sitting all night with an empty plate. With enough information from diners ahead of time, this can be arranged without making too much compromise at all, and depending on time and staff, sometimes something extra can be arranged for a limited number of people (example: making a few extra pies in pots instead of pastry).
But in the end, the best advice I could give to the cook with an interest in authenticity, is compromise only in a way you can be comfortable with. Obviously, the first job would be to deliver food that people can both eat and enjoy but the SCA cook also has an added responsibility and that is in keeping with the theme set out by the SCA which is to re-create the middle ages. If we had no interest in the dining part of the middle ages, then we have little business bothering with feasts in the first place as it would be a lot easier to just bring a lunch or maybe go out for dinner after the event (note: most people pack up and leave after feast anyway, of course we tend to have dinner in the supper hours as well).