Whether one is allergic, prescribing to a certain world view, or following a specific religious practice or diet for health reasons, avoiding certain foods is less of a choice and more of a necessity. For some of these people, eating whatever is set in front of them could contrast deep moral convictions of religion, environmental views, or animal rights advocacy. For others, the cost is physical and can either negatively clash with a doctor recommended course of action or result in adverse allergic reactions.
As someone who suffers from lactose intolerance, I know the difference between choosing to not eat radishes because I dislike them, and avoiding milk because it makes me physically ill. I, and those like me, would eat standard food if we could, but we can’t; this is why so many alternatives exist, like soy milk or gluten-free beer.
I know the difference between choosing not to eat radishes and avoiding milk because it makes me physically ill.
While there are some who tote around a diet as something to brag about, most of us do not feel elitist or particularly special for our restrictions. In fact, it is actually more expensive and difficult to feed yourself while actively avoiding a common ingredient. I have yet to meet a celiac or person with gluten intolerance that would suggest this. Further, gluten-free and other similar options are often priced above regular versions of a dish. Having a beverage made with soy is normally 60-cents more, and asking for a dish with a main item removed will rarely lower its price.
The worst of the food allergies are the ones that do not rely on consumption. Peanut allergies can be triggered by non-eating exposure, and are often met with disdain as people underestimate the fact that exposure could put sensitive people in the hospital. No one wants to be the kid who prevents everyone else in the classroom from having peanuts.
Similarly, it really is not enjoyable having to send back a dish to a busy kitchen that accidentally included something explicated identified as an allergy. In avoiding lactose, I have had several uncomfortable experiences asking a barista to remake a drink for me because they missed the note about no whipped cream. On one occasion, I was told to suck it up and scoop it off the top of the drink, at which point dairy had already melted into it. It is not fair to make someone feel childish for politely asking for their order to align with their diet.
Having a dietary restriction does not necessarily come with liking to give detailed orders, ask for special handling, or explain why they cannot eat what they are served.
Unless you know that someone is avoiding a certain food just for the sake of it, it is incredibly rude to assume that the restriction is not valid. Food restrictions are a very real thing that many people face daily. Someone who cannot or will not eat your favourite food does not deserve to be questioned about the validity of their claim, or to be treated as picky. Give people respect, regardless of what their diet excludes.