A system and method for tracking longitudinal data for the maintenance and management of health of an individual. The method entails marking numerous groceries, drugs, beverages, etc., with labels that may be read by a scanner or reader embedded in a PDA or cell phone or similar small electronic device, and providing users with a suitable scanner or reader. Users scan the labels of the products they consume during the course of a day, and the system keeps track of calories, fat content, carbohydrate content, etc. of the food consumed, drug content of the drugs consumed, etc. The system can also be operated to track exercise levels and energy expenditure during the day. The system is operable to provide a comparative display of various databased information, such as calorie intake versus calorie expenditure during exercise.