I started Primal wanting to lose 70 lbs. So far, with 2 Whole30's, I've lost 19 lbs (10 with the first W30, gained 3 back, then lost 9 on the 2nd W30, which ends on the 31st - hoping to lose 1 more pound at a minimum). Since going primal, I've lost 31.
I think if you're new to primal/paleo, a Whole30 is a great way to detox, cleanse and reset. It really does help with the cravings. But word of wisdom from someone who learned the hard way - starve the sugar demon. Do NOT feed it fruit b/c fruit will become your sugar crutch. Because of this lesson, I will be doing a 3rd Whole30.