The book "Life Without Bread" by Allan & Lutz actually talk about the Japanese diet. Check this book out- it has the best research of any book I've read about LC.

Here's some of what it says:

"In the introduction section for the Japan results, the authors state that in 1958...the Japanese groups had the lowest saturated fat intake and lowest blood levels of cholesterol, and were among the lowest incidence of coronary heart disease. Notice that they used the words "among the lowest." The authors carefully chose their words, because, as we have said, low levels of heart disease were also observed in countries with much higher fat intake.
The trends in Japan from 1958 to 1989 showed that carbohydrate consumption decreased from 78% of total calories to 61%. Fat consumption increase from 5% to 22%. Protein consumption increased from 11% to 16%. Most of these changes were attributed to more meat, fish, and dairy products, and less rice.
In the same time period, deaths from stroke declined from 4.6 per 1000 people to .8 per 1000 people. Cancers rates also dropped slightly, from 4.7 per 1000 to 3.4 per 1000. Myocardial infarction [heart attacks] remained about the same. " (pgs 81-82)

They say more, but I'm feeling guilty for copying this. This book is wonderful!