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 »thinkThin Crunch Gluten Free Reduced Sugar Protein Bars
thinkThin Crunch Gluten Free Reduced Sugar Protein Bars - Crunchy, chewy, & wholesome. Lower carb but not the lowest in sugar.
Read More »