Not that anyone should do such a thing, just a thought experiment. Can’t be too arbitrary like ‘a sandwich’ because you could put anything on it
A loaded meat and bean burrito with all the fixings. Salsa and corn chips and guacamole.
Enough protein, fats, carbs, and veggies (vitamins and minerals). I can’t think of a healthier meal if you were only going to eat one.
Great question, and get ready for the downvotes, but the only actual real answer is raw milk from an animal that is grass fed. Non pasteurized milk has every essential vitamin, mineral, amino acid, and protein a body needs. Pasteurized-denatured milk in the grocery store doesn’t even need to be refrigerated, at least until it is opened; however nobody would buy it like that, at least in the States. So yeah, milk in its purest form is something you could not only live on, you would actually be thriving with vitality.