R > why would you choose "fat free" chicken breast?  If you chose thighs instead, eating enough to get 100g of protein would also give you 90g of fat.  You'd still need more to fulfill your calories, but not as much.

It's a good point and I wouldn't in practice choose the breast meat.  So let's use thighs instead for our example.  Roasted chicken thighs actually give you about 40 grams of fat per 100 grams of protein rather than the 90 you quote above, but we'll go with your super high fatty source of thigh meat.  

Daily calories from that source would be 100 times 4 plus 90 times 9 or 1210 calories.  You can't have any more protein as you're maxed out.  And you can't have any carbs of course.  So you have to find a way to choke down 1700 calories of fat -- almost a full cup.  That would not be easy.

Jim