So why don' we all just get our nutrients from an IV drip for maximum 'caloric efficiency'? Food provides pleasure. Eating tasty food is pleasurable. Calorie dense food is generally tasty. Why would I deny myself? I like potatoes. FWIW potatoes are not a calorie dense food. FFS kunce.
You've inadvertently hit the nail on the head. The only reason to eat potatoes is because you want to.