I never claimed to be an expert magoo. Just said that it was possible to lose weight and maintain muscle mass on a free calorie diet. Before you critisize someones physique i think you should take a look at yourself in the mirror.
it's extremely unlikely. simply put the body reacts to different foods different. this is inarguable. if you get all your protein from soy, all your carbs from sugar, and all of your fat from canola oil you're going to be in a very, VERY different state than if you get them from eggs and oatmeal.
furthermore, if you get all of your calories from protein/fat with a heavy emphasis toward fat, your body goes into ketosis. this doesn't happen when you eat a lot of carbs. all by itself this should tell you that yes, your body DOES differ in its response to nutrient ratios. you can try this any time you'd like, spend a week getting half of your calories from fat using oil, 25% from pure cane sugar, and the other 25% from soy. then do it again, but with 40% of your calories from carbs via oatmeal, and then the rest via eggs and egg whites. see what happens.
if nutrient ratios didn't matter, the RDA wouldn't make guidelines because as long as you got 2000 calories you'd be fine.