The Mozart diet?

I recently started reading a biography of Mozart. And to my surprise, I found a mention of a diet in it. In a letter that Mozart wrote to his mother in 1770. He's been traveling with his father, his sister and this other man.

"I myself have had the privilege of luncing with this saint, who on this occasion drank a whole decanter and finished up with a full glass of very strong wine, two big slices of melon, some peaches and pears for dessert, five cups of coffee, a whole plate of cloves, and two full dishes of milk and lemon. I suppose he might be following some sort of diet, but I doubt it, for it would be too much; and anyway he eats like this at every meal and what's more, stokes himself up with several snacks the afternoon as well."

Mozart: His life and music. by Jeremy Siepmann