I think I know what you mean and does sound paradoxical, but I don't think its unique to raw meat eating. look at the frutiarian folks who eat and than have to take a fruit siesta.
I rarely ever have digestive problems, but sometimes I get the feeling like alot of blood is being pumped to my stomach. eating the same things cooked IME would make me more tired, but I do have suspicious that raw meat does not digest as instantaneously/easily as some claim. Especially for compromised systems. Thats why some prior therapies have their place I think.
ironically after reading this earlier, I ate my words so to speak. I've been living off fish for a few days, hoping markets will restock some GF beef, and my second day eating swordfish it tasted a little off to me (and there was even a huge hole that looked like a worm had gotten at it) and basically lost any interest in eating the rest of the day. no nausea or need to jump to the toilet, but as the day went on I basically felt like I had mild food poisoning. I did try to eat some dinner (haddock) later but I didn't get far. haddock in general makes me queasy even when I am feeling well and only got through a few bites.
on top of that I had to lift a bunch of equipment weighing hundreds of lbs for someone else immediately after eating, just a small amount of dinner after already being off from the afternoons fare - but that was still probably a bad idea.
the whole evening and trying to get to bed was awful: headachey, and lots of upper gas (belching). luckily today I'm feeling better mostly, some mild sense of a headache. but my stomach feels almost exactly the same. no queasy feeling or sense of diarrhea or anything, just like there is a heartbeat in my stomach or something, and no desire to eat.
late at night I tried mixing some charcoal with a whole egg, don't know if that did any good.
I know the Primal folks are really big now on consuming small bits of unsalted cheese before a meal to absorb toxins in the stomach, otherwise meat can possibly putrefy. I'm going to look into this myself.