In the caloric restriction experiments, the nutritional density of the food the animals are fed is almost always increased. Fewer calories, same levels of protein, nutrients, etc. It's not just a matter of 'less'.
From what I've read, humans on caloric restriction diets have to design their diets carefully, to increase the nutritional density of their own food supply. (E.g. http://www.calorierestriction.org/Getting_started)
From what I've read, humans on caloric restriction diets have to design their diets carefully, to increase the nutritional density of their own food supply. (E.g. http://www.calorierestriction.org/Getting_started)