Yeah, obviously. I think everybody should keep a food log and be scientific about what they put in their mouth at first, probably for at least 2-3 months, at least. Then, depending on your goals, you'll be able to add shit up in your head and ballpark your numbers. I'm gaining right now, so I know that I need 3,000 to 4,000 kcal a day right now. I made a diet plan, crunched the numbers, and try to hit those numbers more or less every day. I don't act like a freak in public if I'm over by a carb, but I also don't just throw caution to the wind. Middle of the road. If you ARE prepping for a contest, then that's different.
Like the last dude said, it depends on your goals. If you're just an average dude trying to get bigger or whatever, then do what I said and you'll progress. I'm not the best example, but most of the big dudes have a pretty good understanding of what they're eating.