[CylonBob]

I buy Costco Extra Lean Ground Beef which is <12 % fat. My question is, how do I calculate it's macronutrient profile? Obviously, fat will be 12% * mass. But it seems that different fat%'s have different % of water. Is there any rule of thumb in calculating what % is water and thus what % is protein? I looked online and couldn't find it for 12%.

thanks