There are so many kinds of nerds out there. But there is a big misconception about nerds. Not all nerds are weaklings. The majority of nerds are week because back in the day people were not very health conscious. Im sure nerds now a days care what they eat in their own geeky nerd way.
for example: If a nerd wants to do an all night nerd video gaming session, he will make sure he has enough protein and calories for all the mental nerd activity that goes on in his epic all night online nerd gatherings.
In order for his body to have adrenaline to keep up with leveling up his nerd avatar on World of Warcraft, he needs to pump up his heart and running skills by running away from bullies.