I think we need to look at wine.

When it comes to the glue-er foods...like cheese and bread...
It seems its traditional to drink wine with this stuff...

The reason is some of the gluey type components are alcohol-soluble. So basically drinking wine with some of the gluey meals makes you able to get more out of wheat for instance, with less harm/digestive stress.

I think thats why they drink wine.

Probably how you can have such big 5 course meals... but without wine it wouldn't digest as well...

Seems thats how the French and Italians adapted to their local cuisine... they knew they had lots of wheat, and to make the most of it...it needs to be eaten with wine.