Hey there
My dad introduced me to the blood type diet at the ripe age of eleven. I'm also o-positive, and our suggested diet is, essentially, the hunter-gatherer or paleo-diet. I was reading up the other day, and my analytical brain can't help but notice and point out that each of the individual blood type diets are, in their own right, different tried and true diets that are bound to help anyone lose weight (o positive, for example, suggests lean meats, whole grains, little to no dairy and such, lots of cardio, because we're "predator" mentality. AB diet is basically a vegetarian diet, and focuses on soothing and stretching exercises such as yoga.) I'm not sure how closely tied these things are with a person's actual blood, or whether they're just good effective diets that it would be hard NOT to lose weight on, you know? However, even if my cynical opinion is right, it's my opinion that the hunter-gatherer (o-positive) diet is possibly one of the best anyone could be on, and so I think you'll have really great results if you follow it. I'm also planning to stick loosely to the guidelines. We'll see how it goes!