Lumen is a metabolic tracker that utilizes breath analysis to provide personalized insights into a person's metabolic state. By measuring respiratory exchange ratio (RER), Lumen helps individuals understand whether they are primarily burning fat or carbohydrates for energy. The device offers personalized nutrition recommendations based on individual metabolic goals and preferences. Users can receive real-time feedback on their metabolic state throughout the day. Lumen is designed to be user-friendly and requires no special training. For individuals seeking to improve their health and wellness by understanding their metabolic needs, Lumen can be a valuable tool.