Food diaries are good and can be used in varying ways:
1) Those that break things down into the exact P/C/F ratios for every meal on a daily basis; normally used by people prepping for competitions.
2) Those that keep track of calories, used by those that are either trying to lose or gain weight but don't want to track P/C/F ratios as such.
3) Those that loosely track the meals they're eating without placing either calorie counts or P/C/F ratios alongside the information. With this plan, which may not seem enough to some, you can still add a bit of food here and there or subtract a bit here and there and make the progress you want, since you're still tracking what is occurring.
Some will use a mix of 1 and 2 above etc, and it's not necessarily just people prepping for shows that will use the first mentioned and so on; you have to select what works for you.
If starting with P/C/F ratios seems unnerving then start with meal tracking, then add calorie breakdowns in and then track P/C/Fs as you get more used to things...in this way, it won't feel so daunting for some.
Most people that track their meals will have some idea of the calories within a certain number of those meals, purely because they consume them on a regular basis; it all helps.
It has to be said, however, that no matter which plan you choose to follow, if you don't take a scale reading and maybe tape measure readings of certain points on the body, it won't mean a lot, at the end of the day; you have to have something other than just the food intake to base your results on.
36.5 kg /80.3 lb Middle-Finger DL (right hand)...