A good source of fats that are good for you are meat from animals that grew up eating their natural diets. Unfortunately corn-fed cows and pigs aren’t as good. I still eat them. It’s way better than sugar.
Although cuts of meat vary widely, in general most of the calories in a steak come from fat, not protein. According to Volek and Phinney, you really shouldn’t be getting more than about 35% of your calories from protein; higher often has deleterious effects. As I discuss over in Biology, our ancestors probably ate the fatty portions of the kill first, leaving the leaner, bonier parts for scavengers.
I’m going to need to build out a section of this site specifically to discuss fat. There are a mind-boggling variety of fats. In the interim, let’s leave it that animal tissues of animals raised on normal forage, as opposed to feed lots, have a fat profile that matches well to what your body evolved to process. Nicolette Hahn Niman discusses that in Defending Beef.
Now that I’ve stopped eating potato chips, one alternative are chicharrones from Food City. That’s a hispanic-oriented grocery chain, and those are pork skins fried in their own fat.
Like I said in Avoid Bad, don’t combine sugar with fatty meat products. If you eat a decent steak with vegetables and as little carbohydrates (potatoes, fries, soft drinks, etc) as possible, human-normal appetite control mechanisms will kick in. You get full and won’t want to overeat.