Abstract: A method of adaptively predicting blood-glucose level by collecting biometric and activity data with a user portable device utilizes a portable computing device carried by a user to collect movement data and biometric data about and from the user. Collected data is processed by a blood glucose prediction formula generation algorithm in order to produce multiple blood glucose level prediction formulas. Based on the activity level measured by the device, a corresponding blood glucose prediction formula is used to predict blood glucose levels for a certain period of time. The prediction formulas recursively provide feedback and change for successive iterations and new formulas are generated as new data is collected.