I've done Atkins off and on for years with successful losses. I think you could look at PB as similar to Atkins because it emphasizes meats and veggies, eschews sugar. However, PB places emphasis on eating natural/whole foods without additional processing or preservation. Atkins (especially now that he's dead) doesn't seem to mind if you eat an Akins bar full of crap, artificial sweetners, etc as long as it's low carb. Atkins also focuses on losing weight, but not so much on overall health, wellness and exercise. I don't watch my ratios as closesly as I should to be considered completely primal. However, I do eat whole, natural, organic, wild caught or grassfed foods. I leave off processed foods, sugars and artificial sweetners. I don't compare almonds to walnuts to cashews because I don't really care to take it to that level. I supplement with high quality omega 3's and eat fish occassionally and figure that's about as good as I'm going to get. I don't count calories, I don't count carbs (mostly estimate). I DO care if I'm in ketosis because that's the only way I can lose weight and maintain natural appetite suppression.