I use Waistline. It pulls food data from OpenFoodFacts and has support for meals and recipes as well, although I mostly track weight not nutrition.

There are several on F-Droid. There's Energize and Food You, which integrate with some external food databases.

This just came up the other day on !fdroid@lemdro.id https://lazysoci.al/post/28964710

Calorimeter

I'd consider a web based one, not android specific but they run anywhere on any browser.

I found https://cleanslate.sh/ to be interesting, and it has a lot of very useful info attached on foods/exercise in a very no bullshit fashion.

There's a few others if I search github that are selfhosted, might not be your cup of tea though.

The biggest issue with Foss apps is their food dabase isn't as likely to be as good as the paid ones

An issue I came across with the calorie apps on f-droid is that there isn’t one that simply lets me set a calorie goal/limit, and then lets me enter calories throughout the day and shows the running total and the remaining calories allowed. Basically I just want a special-purpose calculator app.

Please don’t force me to select what food i ate for which meal; just let me enter numbers.

kids these days, back in my day we just did our disordered eating by pen and paper /j

OpenNutriTracker?