The US military has great interest in more comprehensive measurement and tracking of metabolism, both for optimizing the performance of warfighters under demanding physical conditions and for maintaining the health and wellness of troops during and after their military careers. While sensors for making metabolic measurements have existed for decades, they are expensive, some instruments primarily intended for clinical or professional use. MIT Lincoln Laboratory, in collaboration with the US Army Research Institute of Environmental Medicine (USARIEM) and the Marine Expeditionary Rifle Squad has undertaken a research effort to create a low-cost personal metabolic sensor and an associated metabolic fuel