This invention has three distinct elements:
- First, a wearable respirometer that measures pulmonary ventilation and the carbon dioxide and oxygen levels of expired breath, and calculates whole body Respiratory Quotient (RQ) (i.e. the ratio of carbon dioxide produced to oxygen consumed in expired breath). This wearable respirometer can be used to: measure metabolic energy expenditure (metabolic rate) both at rest and during physical activity, estimate the metabolic fuel mixture (carbohydrate to fat ratio) being metabolized to meet the body’s energy demands, and assess an individual’s aerobic fitness (maximum rate of oxygen consumption).
- Second, an austere State Model of Fuel Metabolism that uses respirometer data (input) to generate (output) to provide individuals with useful [actionable] information regarding their metabolic state. Specifically, the State Model of Fuel Metabolism graphically illustrates how users’ diet (food amount, composition, and timing of consumption) and physical activity (exercise type, duration, intensity, and frequency) affect how carbohydrates and fat are burned and/or stored. The feedback regarding metabolic fuel use, which is characterized by an RQ measurement, enables individuals to tailor their diet and physical activities to achieve and maintain a desired pattern of fat- or carbohydrate-predominant fuel use, which will lead to desired changes in body composition (fat and muscle mass) and physical endurance/performance. The wearable respirometer and State Model of Fuel Metabolism can be employed by a broad demographic of individuals to improve metabolic health, minimize the likelihood of type 2 diabetes, and improve endurance exercise capacity.