Going to the toilet is inefficient, that's why I only eat precisely the calories and nutritional content that my body needs without anything left over to produce waste
Unfortunately that’s not how the body works. Waste isn’t produced because of excess intake. That’s what causes far buildup. Anything you eat and drink will create waste.
"Going to the toilet is inefficient"
By what meassure? To me it is by definition part of every living metabolism.