Mmm... Cows weight like 5 persons, 5^(1/3)=1.7, so 4%*1.7=7%, so 170 kcal that is still less than a single cheeseburger.

Marvelous...

Finally a good reason to assume a spherical cow!

The square cube law pops up all over the place, my favorite being in fusion reactors, where it is a two edged sword.