Fitness

I use text messages and send to a blocked number, such as 555-0100 (any area code) and that way I never need to worry about the app crashing or them paywalling useful features after becoming reliant on the "free" app.

It's extremely simple and you can add that person as a contact and give them a name such as "calories" or whatever you find useful. You can then pin that conversation to your text messages so it's always at the top of your texts.

Screenshot as an example: https://i.imgur.com/HpLM2yu.png

Best of all, it doesn't require a specialized app, which can be shut down or made unusable at anytime. You are at their mercy, which is their business model once they sell or start paywalling their most useful features.