Really only about 1.5 years for me, but this is still the longest I have "stuck with" any sort of "diet program." I have allowed more of the 20% in lately, but still no on the gluten grains, legumes, etc. I can proudly say I have not eaten a bagel in nearly 2 years. Of course, I have allergies encouraging that.
Sticking with it, though. It is nice to still fit in my clothes. It's a good weight/size maintainer, even if it's 80/20.
Stumbled into Primal due to food allergies, and subsequent elimination of non-primal foods.
Start Gluten-Free/Soy-Free: December 2012; start weight 158lbs, Ladies size 6
Start Primal: March 2013, start weight 150lbs, Ladies size 6
Current: 132lbs, Ladies size 2
26lbs lost since cutting the crap.