> > how do you even guesstimate fat content?

Try "75% lean" grassfed beef burgers.  They're the perfect no brainer food as they have the ideal fat to protein ratio.

And I'm sure you've seen this site: www.nutritiondata.com

By the way, I said that Phinney's recommendation is for 15% calories from protein, the rest from fat.  Here's a better way to look at it.  You should consume from 1.2 to 1.7 grams of protein per day per kilogram of ideal body weight.  That's 80-112 grams protein per day.  Going slightly above that is ok, but I'd never on average go below 80 grams per day.  Make up the rest in quality fat.

Jim