"What about dietary restrictions due to health or allergy reasons? This is an issue in our home and it is so hard to find common preferences (although we haven't stopped trying!) and going to parties and stuff is really hard (we usually bring our own foods to such events, but I feel like it still singles out the child who can't eat what everyone else is eating and it's not always possible to make something that looks the same, plus I don't have the energy to make an exact big replica birthday cake for every bday party, nor the money.)"
What exactly is the problem?
Is it that replacement food doesn’t taste as good?
Is it that child chooses to eat food that causes health problems?
Is it that having food allergies, by definition, makes a person different from people who don’t have allergies?
Is it something else altogether?
If the replacement food isn’t as good, then it makes sense to me to keep working on finding better replacements. That might mean more time baking, and then freezing options that are really appreciated to have on hand when occasions arise. It might mean thinking outside the cake box, and bringing favorite candies or fresh seasonal fruit or a yummy custard, or homemade ice cream, or whatever will be more delicious for the child than the expected cake.
If the child’s allergies are mild enough, or if the dietary restrictions are such that some flexibility exists, then it makes sense to work together to figure out what the actual parameters are… I’m thinking of adults I know that do things like take enzymes so they can eat dairy in spite of being lactose-intolerant, or make sure they eat enough protein to balance a small piece of birthday cake without impacting their diabetic blood sugar. If that is not an option for obvious health reasons (anaphylactic shock comes to mind), then it’s not an option.
If it’s about being different, well… We all are. It might help to actively notice the positive differences – the things people enjoy, that make their differences seem wonderful instead of unfair. It might also help to bring enough of the safe dessert to share with others – then the boundaries blur, and it’s more like potluck eating, where individuals pick and choose what works for them.
For what it’s worth, sometimes kids without any dietary restrictions aren’t interested in desserts at birthday parties. Some people don’t like cake. Some people don’t like frosting. Some don’t like ice cream. Usually, everyone doesn’t want exactly the same thing. Some want a corner piece of cake with no ice cream. Some want just ice cream. Some want it all. Sometimes people get very excited about the dessert they see at a party, and are horrified by the flavors once they bite into it, and don’t end up eating more than a nibble. The people that are all the same are actually NOT all the same – they all have different tastes and different eating styles.
Also, eating and enjoying the dessert are not essential for having fun at parties, yes? It’s possible to become almost obsessive about something that, when seen through a different lens, can seem trivial. I think that’s a very common problem with food restrictions – we are, by definition, focused on what we can’t eat. Just figuring out how to reframe our experience can help a lot in such a situation. I think developing a good working list of all the amazing, delicious food that people can eat, whenever they want, can help take the pressure off. Maybe having fancy desserts at home on a regular basis will help normalize the experience of dessert to the point that missing one at a party is irrelevant.
Another possibility – become the resident birthday cake expert. Offer to make desserts for friends' parties. Bring amazing desserts to all potlucks. Many people are thrilled at the thought of having a friend help them out by making the cake for them – don’t be afraid to offer. Or maybe there's a brand of ice cream that is safe, offer to bring that. Whatever works.
I know first-hand how challenging this situation can be, and how hard it is to avoid feeling self-pity when faced with food that looks yummy and is off-limits. I hope that something here helps, even just a little.