The Benefits and Uses of a Diet Diary Keeping a diet diary is one of the best decisions an individual can make in their aspirations of maintaining the healthiest possible lifestyle. A diet diary enable individuals to live their life in an order of discipline that not only keeps them aware of the calories they are consuming throughout the day, but also what exactly they need to meet their fitness goals. Any type of fitness enthusiast can benefit from a diet diary, including bodybuilders, athletes, or anyone that is simply looking to lead a healthier lifestyle. A diet diary keeps people aware of the trends they implement in their lives, which is something many can lose track of without one.