Lumen is a metabolism tracking device that measures CO2 in breath to determine whether the body is burning fats or carbs, helping users tailor nutrition for weight loss and metabolic flexibility. Designed for weight-loss seekers, athletes, and biohackers, Lumen combines a handheld breath sensor, a personalized daily meal plan, and workout recommendations through its companion app. The platform's daily metabolic readings adjust macros automatically based on lifestyle changes. Lumen is a strong fit for health and fitness creators who want a metabolism tracker to recommend to audiences interested in data-driven weight loss and nutrition.