Why recursive function consumes more of processing time than loops?

[csr]

This is why using recursion shouldn't be taken for granted. The use of resources can easily become exponential; and the more resources are used per function call, the worse it'll be.

While recursion can provide a simpler and more readable solution to a problem, you'll be able to achieve similar results if you use the right tools. For instance, this code:

def fib(n):
    fibs = []
    for i in range(n + 1):
        if i < 2:
            fibs.append(i)
        else:
            fibs.append(fibs[i - 2] + fibs[i - 1])
    return fibs[-1] if n >= 0 else 0

Provides the same simple solution by making use of a list to save and use the results as we iterate from 0 to n (included). The memory footprint in this case is minimal (only one function call and a list), as we don't take additional steps to keep track of n-1 and n-2 in order to calculate and use these.