For those that are serious about what they are putting into their bodies because they know they have to exercise in order to get the most benefit out of those calories. Keeping a log of what you eat each day can be a very helpful reminder of how much you will need to exercise in order to turn those calories into fuel and muscle mass.  Some monitors and or heart rate monitors have the capability to let you input what you eat so a running digital log can be kept.  This data then can be exported out for a more detailed analysis by you at a later time.