I’m a type O and did the paleo diet for 2 1/2 years. It made me sick!! I’m so much better eating plenty of carbs, so no, I don’t think it’s just a blood type thing. I think that maybe those people who are “doing well” on low carb are actually not doing well. They just have hidden problems. Maybe I’m wrong, but really, how good for the body can it be? I have wondered though if it’s a genetic thing as I certainly seem to need more carbs than other people. I have a friend who’s been on paleo for years and she seems to be thriving. But I still wonder. Is she ignoring how she really feels because she’s nice and thin? That beautiful figure can be very deceptive.