As a weight lifting woman, I ingest at least 0.75 grams of protein per pound of lean body mass per day. This fits the type O diet, but people who are type A's who weight lift intently also follow this plan. (Men do 1 - 1.5 g of protein per lb. of lean body mass). For me, that's 21% - 28% protein, but for a man of the same lean body mass, that's 33% - 42% protein.
I don't know where this guy is pulling these figures from, but the amount of protein you ingest is partly dependent on what you do (how much muscle you tear down and how much needs to be rebuilt by your body). You cannot make it dependent simply on your blood type. ER4YT stipulates ketosis and high protein only for O's, but there are plenty of A's who rely on chicken, fish, olive oil, and flax oil (as well as avocados and a variety of nuts and seeds) to stay in ketosis, keep protein high, and lift weights on the same schedule as O's. In fact, when I read ER4YT, the author confronted this question of A's who thrive on O type exercise with no real answer. He suggested (without evidence) that in spite of the pleasure that some A's get from intense exercise that it is still not good for them, and he raised the possibility that there might be a "twist" for some A's who thrive on O activities. And he did admit that there's a lot not yet known. Given those choices, I would go with the third one and say that ER4YT is a great starting point, but the adaptable human body has to be measured in terms of that it does and not just what it is.
The absence of longterm studies that are specific to ER4YT has hindered the diet's effectiveness in many ways, as well as its believability, especially for serious athletes. I advocate it, except when it comes to "across the board" dictates that base everything on blood type alone. Many, many type A's excel at type O athletics and thrive on the ketosis diet as long as beef is eliminated and there is a lot of flax oil or olive oil. I think that Dr. Dadamo was never so right as when he observed that ER4YT is only a starting point, and there is a lot of research left to be done.
So, to put in my 2 cents: no diet should be as low in fat as 8%, nor as high in carbs as 72%. Two tablespoons of oil a day is a minimum, and that would be 12% fat in a daily diet measured by calories. The adjunct to this is that no diet should be viewed only as what you put inside your body. What you do with your fuel is also crucial. Eating right loses its effectiveness if a person is living a sedentary or high stress life. And no diet can accomodate completely to that lifestyle. You must get out and exercise. Failing to do so is as catastrophic as an O sitting down to a pizza or an A sitting down to a 16-ounce steak or a B having a bowl of shredded wheat.
Just my opinion.