- Unflavored casein protein powder (mix with water, glug down like milk) - Quality multivitamin / supplements - Pectin and/or psyllium husks (fiber) - Spoonf

- Unflavored casein protein powder (mix with water, glug down like milk) - Quality multivitamin / supplements - Pectin and/or psyllium husks (fiber) - Spoonful of extra virgin olive oil - Electrolyte drink (salt, potassium chloride, magnesium citrate powder, and vitamin C powder; add water until it's tolerable to drink) That gives you most of what you need with no prep other than adding water. It wouldn't taste good, and I wouldn't advocate doing it for a very long time without eating real food. But I've eaten along these lines as part of some experiments I did on myself, and I had no gastric distress other than that I needed the fiber to not get backed up.