You're channeling correlation pretty heavily there.
It's just based on experience. Paleo is almost exactly what I did for years when I wanted to cut before I ever heard of Paleo, minus maybe some Oatmeal, peanut butter or a bowl of cereal here or there. No grains means no pizza, bagels, bread, pasta, cakes, cookies, cereal, battered whatever, waffles and just a ton of stuff you should limit if you're trying to lose weight. You can eat all that and lose weight if you count calories, but in my experience you'd feel like shit and be very hungry. Which is why most people fail hard on diets. Blood sugar spike, insulin, hunger AND add on exercise and it's no wonder they fail.
Bodybuilders will always go on about hitting their macros, the foods paleo calls for makes hitting them almost automatic if you're not retarded about it, or good enough for people who arent looking to get to 4% BF and go on stage. It also makes cutting calories, another mantra you always hear: calories in < calories out, much easier in my experience. I dont have to count at all yet and still losing. There's no magic. It's less calories, more satiety, quality food. The real key though is that it gets past that awful fucking advice to be scared of fat and meat, and eat more "whole grains".
Finally, when you eat at 80% compliance, you have plenty of room for pizza and ice cream. Within reason.
It's a great framework. I like it a lot. YMMV
