My opinion is dont wory about trying to condition yourself to accept less food, in fact, have a good feed before you go! I was on an escape and evasion course with the Army and there is no talk of conditioning prior to it. One day your eating fish and chips from Tonys chip shop in Aldershot, on top of a few pints, next your on the run in Bavaria, foraging as you go. Physical and mental fitness help, as does having a role or tasks to occupy yourself. I daresay if you were sitting beside a light aircraft downed in Alaska waiting for rescue, food , or the thought of it, would occupy your time. In my case, I was paired up with another, on the run for 7 days( after a 7 day instructional phase), with objectives to meet. No time for fishing, trapping, just foraging en-route. As has been mentioned, we eat more than we really need in everyday life. A lot of this is through boredom, and in the relatively short time span of a course we can subsist on very little. i dont know the syllabus of the course you are going on, but presumably there is an instructional phase, then an exercise phase, where you put lessons learnt into practical use. In this case it is important to focus on goals, short term ones, and keep occupied. The very fact you are considering going on a course of this nature indicates you have the right characteristics. Be good to hear a folow up on how it goes, good luck, Mark