I don't do this very often, but here's my recipe for a liquid high-fat breakfast, which I just consumed.
– 4 oz heavy cream / 480 fat cals, 0 protein, 0 carb
– 4-5 oz canned coconut milk / 300 fat cals, 0 protein, trace carb
– 1 whole large Omega-3 egg / 45 fat cals, 25 protein, trace carb
– 1 packet of Splenda sweetener / zero
– Tbsp vanilla extract / probably a few carb cals
Toss it all in the blender with sufficient ice to make a nice shake, and then enjoy yourself. We've got about 850 calories, 825 or 97% of which are fat calories. Not for everyday, but it's one way to keep the calories up on a low-carb diet without overdoing the protein. Usually I'll do two, or even three eggs, but I eat so much meat that I sometimes am looking to just get a big fat dose.
I know. It's complete heresy. Consider this: If you were going to design a biological being and had three macro nutrients at your disposal, two of which possess 4 cals per gram (carbs and protein), and another that possesses 9 cals per gram (fat), more than double, which one are you going to design your being to run on fundamentally, with the others as back up? Which one of those does the human body store, sufficient to fuel operations for 2-3 months without any other nutrition? Carb stores (glycogen) can be completely depleted in two hours of strenuous activity. Think about it.