So far as I know, the oldest in the English language at least, is Banting's Letter on Corpulence. Having lost weight and dramatically improved his health on a low carbohydrate diet. Banting wrote and self-published the book back in the Mid-Victorian era, and he distributed it for free.
Read More »The CarbSmart Library – Low Carb Keto Books & Cookbooks
The CarbSmart Library - Low Carbohydrate Diet Books and Cookbooks - over 100 low-carb cookbooks and carbohydrate counters. No matter what you're looking for, CarbSmart is your low-carb reference library.
Read More »