Statistics work in your favor here though: at 2,000 kcal a day over a month, you'll consume 56,000 kcal total. So the question isn't whether any given thing was or wasn't some value - it's how much of a buffer is in your "unknown" chunk of that month that you're not winding up way out.

Like if you just tracked the things you can track, and noted the number of occurrences you didn't, then your end of the month weight will tell you whether you're overshooting or not, and you can estimate what proportion the "unknowns" might represent (and whether you should put a conscious effort into reducing them.