I've been maintaining a personal calorie tracker (keeps me entering), and using claude for entering meals has been the perfect experience.

One of my favorite features has been giving a recipe url and having it figure out the calories for that recipe with line-by-line entries for each ingredient. Then it keeps the extracted recipe in markdown format for the next time I want to make it.

Substitutions are also great - "I'm making [such and such recipe], but with half the sugar."

One of the others has been "I had a meal a couple weeks ago at [x restaurant], can you enter that again for right now?" Having the long-term context for entry has been excellent. And a related one, where I upload a photo of the menu, and say which menu items I'm eating and it puts together an estimate for the calorie count.

I lean heavily on a long auto-compacting claude code session for all of this. I have a UI for graphs, history, and simple entries, but claude's been my favorite means of entry by far