I've been 23 days Primal and I felt great within days. The first 3 or 4 days were a short and mild carb-flu; yeah it happened pretty quickly. Then after that I felt amazing! And it has been that way ever since, except for this morning after consuming apparently too many sugar filled cookies. Oops. Live and learn, right? You'll probably experience a similar feeling if you try any of your old usual foods. It's lunchtime now and I am feeling much better. But it appears for the most part, the great feelings last!