Avoid popup "Save changes?" when nothing was changed in Excel

[msoff20xx]

Whenever I open some Excel docs to have a look at the content table and want to close it afterwards WITHOUT CHANGING ANYTHING then Excel (2003/2007) asks me

if I want to save the changes.

I think Excel automatically re-calculates embedded formulas even if I did not type in manually stuff.

So Excel thinks I made some changes.

How can I tell Excel to NOT prompt me any more to save changes if the changes are only based on formula re-calculations ?

If this is not possible: How can I tell Excel to automatically save all changes without prompting me?

Is it possible to setup this preference for ALL excel docs at once rather than for each Excel doc individually ?