I don't know about the bulletproof part but my standard is 4 fl.oz coconut milk + 8 fl.oz water in a saucepan on medium until the first wisps of steam, then add 2 tbsp cocoa powder + sweeteners/seasonings of choice (peppermint, vanilla, etc.) with a wand blender.
Lots of: urban hiking, cycling, sprinting
Lots of: fresh meat, seafood, eggs, organs, tubers, starch fruits, vegetables, meat fat, dairy fat, oil fruits
Some: cured meat, dairy protein, sweet fruits, rice, pulses, tree nuts, oil seeds
Minimal: soy, refined proteins, sugar, liquid carbohydrate, grains, refined oils, peanuts