Fain's description which you quote as > however his neck was a little short and he had perhaps already too much belly.'< is, in my source, specifically dated to the time of his second marriage.

Countess Potocka dined with the family: 'Napoleon ate little and very fast. the simplest dishes were those he preferred.......The Empress, on the other hand, was engrossed by the dishes offered her, reused none, and seemed vexed at the speed with which they followed each other.......Just as we were about to leave the table, the chamberlain came and informed the Emperor that the Viceroy of Italy was awaiting him in the garden. He started up, giving Marie-Louise no time to finish the ices, which vexed her so much that she could not resist complaining to her uncle.'

It does not sound as if the second marriage was responsible for Napoleon's weight gain, I think the possibility of a pituitary problem has been suggested.

Susan