Auto Update Data Validation

Here's the story... This is not how I am applying this, but it's a good analogy.

Cell A1 has a drop down list where we can select breakfast, brunch, lunch, or dinner.
Brunch is only available on weekends...

So we set up the drop down list as an Indirect option for cells A5-C5. We autocode those cells such that on Weekdays, A5=Breakfast B5=Lunch C5=Dinner and on weekends, A5=Brunch B5=Dinner C5=""

Here's my issue and what I'm hoping VBA can solve through some sort of auto update feature.

If I saved the spreadsheet on Friday with A1 as breakfast, when I open the sheet on Saturday, A1 will still be breakfast. I will have to manually click on the dropdown (breakfast won't be an option), and then select brunch.
Following?

Can we code the sheet to update cell A1 to automatically change to the new value when we open the book or select the sheet, etc?

Bump... Kaper's response was not especially helpful.