The teachings in the book have some overlap with Dr. McDougall's plan, but Dr. Shintani -- at least in this book -- seems more concerned with the glycemic load of foods. He does say that fat consumption should be low, and the focus should be on whole foods, but obviously he thinks a little oil/meat/dairy is okay. So really, the message is not the same.
Dr. Shintani says in his book:
On page 338:
"As you know, I don't recommend the use of animal products. However, the Good Carbohydrate Plan is flexible enough to include them....."
I assume that some of Shintani's patience are not willing to go completely plant based so he takes this stance.
One of his 10 carbohydrate myths (#4) is that high carbohydrate foods raise insulin levels more than meat. For example, beef raises insulin levels 27% more than pasta. This is because protein stimulates the release of insulin even though it doesn't raise blood sugar. (Which goes against all the high protein/low carb advocates blaming the insulin repsonse on weight gain. The important message is that the good carbs (the starchy ones) are the ones we should eat.)
I find Shintani's work very much in step with McDougall's message.