So I set up a global hotkey on my mac via icanhazshortcut that opens/generates a text file in Sublime Text with the current date in the filename and set up a hotkey within the editor to insert a timestamp. I've established a syntax that's basically [keyword] [number] that I can use for tracking food calories, fitness, etc. I can record I ate a couple of yogurts via just two keyboard shortcuts and typing 'yogurt 2'.
And now I'm building an app that reads and processes those files and puts stats in a database or exports to some app for analysis (just the former for now).