I suspect a number of people who’ve bought my food (in some cases, I know) don’t use meters. They just think it’d be nice to get some yummies for their avatar.
The potential hiccup is that they may not know how to make the food behave or why it behaves like it does.
So a super-short introduction: The Azora, Spellfire, and Spellfire 2 meters are made by Aaron Cerveau and are for the purposes of roleplay and combat. To my knowledge, they are the only meters that require the consumption of food (rather than just being combat meters).
All of the Azora and Spellfire food I sell (and others sell) is made using script kits that Aaron sells. Azora and Spellfire food (Spellfire 2 is a bit different) can be used by anyone, though. The food can still be clicked (and thus eaten) without a meter on. Azora food requires an activation key. The keys are sold separately.
My advice to non-meter users who are interested in metered food? Buy the Spellfire version, if it’s available. The scripts are different–Spellfire can only have 10 food prims in the build, so it’s simpler–but if the Spellfire version is sufficient for your needs, it’ll save you having to buy a key.
Of course, if you use a meter, use the right food. :-p