Thank you! I’m really excited to see that you have been doing some research into GIs and carb counts and calculating your own FPs. There certainly is some variability out there in terms of GI and carb counts depending on the source.
Most of my data came from the data base of Dr. Jennie Brand-Miller (One of the worlds formemost authorities on the GI) who gave me permission to use the GI database for the book. But I continue to challenge that database myself as new information is published. For instance, recall the dramatic increase in the FP for dates. As for carb counts, many came from that data base, but, like you I look at different sources including: http://ndb.nal.usda.gov/, http://nutritiondata.self.com/, http://www.mendosa.com/, and directly off foods labels from reputable companies.
Please keep in mind that this is a new system and there will be updates, adjustments and corrections over time. One big update one is working it’s way through the system with 60 new entries from the first FP data base as well as some corrections. This one mostly affects the first printing of FTD Heartburn as it was published over two years ago (the FTD Heartburn ebook is live with the changes, the print book will follow in about a month). We are also reprinting the IBS book this summer but the updates will not be nearly as extensive. There are some that affect both books. For instance there was a typo for the net carbs of Yams. Here are the correct values for Yams: 5.3 ounce serving with a GI of 66 has 34 grams net carbs, 6 grams of fiber and the FP is 18 grams – high.
I did anticipate that inquisitive readers / researchers like yourself would eventually become involved helping move things forward by adding information and challenging the existing data. I could not be happier that you and a couple of others have joined in.
I would be glad to connect off line if you want to compare notes. Just contact the Rhea.firstname.lastname@example.org and ask for me.