To do Alt + W J on Mac in Excel, download and install Accelerator Keys, then press Option, followed by W, J.
Command: Zoom To 100%
This is how to do Alt + W J on Mac in Excel with Accelerator Keys, the native ribbon and alt key shortcut solution for Mac users who get more done with Excel.
Alt + W J zoom To 100% resets the worksheet view to its default zoom level. This restores normal viewing size after zooming in or out.