Protein is the number that earns the effort
If you track exactly one thing, track protein. It is the macronutrient most strongly tied to keeping muscle in a deficit and building it in a surplus, and it is the one most people underestimate by a wide margin when they guess.
A practical target for most people training seriously is between 1.6 and 2.2 grams per kilogram of body weight per day. Hit the bottom of that range consistently and you have captured most of the available benefit.
- Weigh protein sources for the first two weeks to calibrate your eye
- After that, estimate portions you eat regularly and weigh new ones
- Track the daily total, not the timing, unless you are competing