To do Alt + M X E on Mac in Excel, download and install Accelerator Keys, then press Option, followed by M, X, E.
Command: Automatic Except Data Tables
This is how to do Alt + M X E 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 + M X E sets calculation mode to Automatic Except Data Tables. This mode recalculates all formulas automatically except for data tables (What-If Analysis tables), which can be slow to recalculate. This balances performance with automatic updates for most calculations.