I'm not sure I understand your reply: Protein: OK, add to the hypothetical experiment enough protein shakes. Carbohydrates: their inclusion in your list seems t

I'm not sure I understand your reply: Protein: OK, add to the hypothetical experiment enough protein shakes. Carbohydrates: their inclusion in your list seems to suggest that a calorie is not a calorie, in the sense that one can't substitute all one's carbohydrates with fats, as long as the calories add up to the same amount. Right? Fats: Mayonnaise has quite a lot of fat. Vitamins, minerals: Take enough pills of those. Water: OK, drink water as much as you want. Would a person living on this diet be healthy? If not, and we controlled all the non-caloric variables, does that mean that the premise that "a calorie is a calorie" is false?