[whiddershins]

For another random data point:

There's an old book called "Life without bread" that was a pre-Atkins low carb diet written by a German Doctor named Wolfgang Lutz. He claimed that, after much trial and error, 72 grams (about 6 slices of bread) was the cutoff, and further restriction didn't particularly help patients in any measurable way.

Leben Ohne Brot (Life Without Bread) http://www.amazon.com/Life-Without-Bread-Low-Carbohydrate-Di...