The Benefits and uses of a Food Diary When it comes to one’s health, it is important to ensure that the individual is aware of the things they are eating throughout the day. A food diary can keep an individual in check, without breaking the amount of calories they may have limited themselves to in order to reach specific goals. A food diary is something that is beneficial for anyone that has set themselves to live by strict and disciplined rules. Keeping journals are a way for people to keep themselves aware of the things that they may forget. Students write notes in journals to keep from forgetting the materials they learned in class so that they can succeed on their tests.