My idea of the day is to draw up a rough-idea grid of calorie counts in different classifications of food - not "chicken", "pizza" and "beer" but "bad", "so-so" and "good", with a breakdown of portion sizes, "small", "medium" and "large". From this, you should be able to get a good enough idea of your calorie intake without needing to look up the difference between white rice and brown rice. We're sacrificing some precision for better usability. You do need to know enough to say whether a meal is good or bad, and that might get subjective, but how much difference does it make to your system if you think you've eaten 50 calories instead of 60?
So here's my chart. Consider it a work in progress, able to be tweaked if you want, but remember the goal: simplicity over precision, but maintaining accuracy. By all means, adjust the values, but if you start trying to add in the difference between chicken and beef, stop.
Mokalus of Borg
PS - It's weird, but I put off writing up this table for weeks.
PPS - I guess I thought it would be hard.