Does including a file with lots of functions slow down PHP applications?

In PHP, include a file with a lot of functions when u only use let say half of it.

But the reason to do it because if application go bigger, i don’t have to include many files.. just one is enough.

let say, i can include
userFunction.php – login, register, edit account…
dataFunction.php – all the activities related to data.

so in the page like add new data, i just include dataFunction.php…