MREs if nothing else, in the Army we were taught how to carry our own excrement to hinder enemy intelligence and in some units you don’t leave scat at all on a mission, the Pentagon needs to follow security measures.
The US Army Special Forces S.O.G. teams in Vietnam, who carried out cross border missions into Laos, and Cambodia, would routinely spend the 72 hours before a mission locked up. Partly for security, and partly so that the Americans, ate the same food as their Montagnard team mates, so that North Vietnamese Army troops hunting them across the border, could not tell from the scat that there were Americans in the area.