I attended an ASME sponsored talk about 10 years ago at Princeton that featured an SR-71 pilot (he was selling his latest book).
The dicussion was one of the best lectures I ever attended for the technical aspects of an amazing aircraft.
Notable for this thread, he stated that their usual preflight diet was a high protein... steak and eggs, as I recall. Said it bound them up pretty good for long missions to the other side of the globe.
In flight they had astronaut type food... and they could heat it by placing it in under the windscreen the front cockpit. At the speed at which they were travelling (Mach 3) the friction energy was enough to heat the windscreen and radiate heat to warm the food packets.
The SR-71 was a magnificent beast. Thanks!