They are definitely related, but cooking and nutrition are different sciences.
Now let's add another: Gastrophysics. It brings human behavior to eating, and explains things like why we eat more food when there are more people around, and why ketchup is just not considered palatable if it's green.
Charles Spence at the University of Oxford gives us a crash course in his book Gastrophysics: The New Science of Eating.
Grab radio, fork, and knife, and hear the news about what we chew.