Hemsworth did not eat 6K calories leading up to the shoot. You burn fat by being in a deficit. How high would Hemsworth's BMR have to have been to burn fat quickly at 6K? They all say this same exact balonie, and maybe they did increase calories drastically very early in the program. Drugs don't change this that much. That Swedish guy who did Tarzan said the same thing. There are no Olympia competitors who diet on 6K, 4K maybe at most. But many need to go down to under 3K at some points.
Yes they eat a "ton" of food. In VOLUME, not calorie density. Salad and salmon and things like that. It might even be hard to consume it all while you're really starving.