Dr. Gee:

Again, it's best not to ask how humans survived before the discovery of statins (or "red yeast rice", if you prefer the herbal version).

JS

kacper:

The "six pack problem" is way beyond the purview of a single comment.  Furthermore, it's difficult to do without unnatural dietary modifications that are neither "paleo" nor healthy: see the classic article You, too, can't have a body like this.  

That being said, the bodybuilders and weight-class athletes (e.g. powerlifters, MMA) have you covered on that score.  Look into cyclical ketogenic diets like Jamie Lewis' Apex Predator Diet (warning: his site is extremely NSFW).

JS

kacper:

You're not going to find a "six-pack diet" that doesn't involve some amount of misery.  Look up "cyclical ketogenic diet", "Velocity Diet", "protein-sparing modified fast"...or just suck it up and use Jamie's, which I already linked above.  

Paul:

I tend to agree.  Yes, there are a few men who sport a six-pack on any diet...just like there are a few women who have natural E cups.  However, they're rare.

Rita:

The point is to eat in a way that allows us to reach our full potential as humans -- strong, smart, and healthy.  If you just want to get as lean as possible, see my reply above to kacper.

jason:

If you want to lean out:

-Go much higher on the protein and lower on the fat...i.e. leaner meats

-When you eat fat, make it coconut oil whenever possible

-More vegetables

-NO PEANUT BUTTER.  It's incomplete protein and a whole bunch of omega-6.  Peanut butter is not part of this diet!  I suspect this is a big part of your problem right here.  I'd ditch the other nuts, too, for similar reasons...most aren't as bad as peanuts, but they're calorie bombs and not all that nutritionally dense.

-NO SNACKING!  You don't lose fat if you're constantly snacking.  Either fix a meal or suck it up.  And if you can't go between meals without snacking, either you didn't eat enough or you're still not fat-adapted.

-Go easy on the fruit, and only eat it as dessert -- no between-meal fruit snacks

Let me know how this goes for you.  Remember, there is also the possibility that (depending on what you ate before) your body is simply stocking up on nutrients it hasn't had for a long time.

JS

Mike K:

If you're managing to lose muscle on a 40% protein diet, you're not eating enough food. 

Paleo foods, being nutritious, are far more satiating (and sating), per calorie, than processed foods...so if you're eating to the same degree of satiation that you were before, you're very likely to be eating less food than you were before.  (Total up your calorie intake on something like fitday if you're curious.)  If you were weight-stable before, the likely result will be weight loss.

Fortunately the solution is simple: eat more food! 

JS

Mike K:

Then you need to increase that number until you stop losing weight.  

It's certainly not a protein shortage...if you're eating 40% protein calories at 2200 kcal/d, that's over 200g/day of protein!  It's very rare that I'll ever say this, but you need to increase your carb and fat intake.  For leaning-out purposes, make that fat coconut oil.

JS