This is an aerial photo of the Portus Project excavations in 2009. Credit: Portus Project
I think this is probably true, although I am not thoroughly educated on the subject and especially ignorant about the gap of at least 200 or 300 years between the fall of Rome and the conquests of the Mediterranean by Islam beginning no earlier than 620 A.D.
This was a comment I posted on your recent thread in which I cited the theory that the European dark ages were caused, or at least precipitated, by the advent of Islam and the shutting down of the Mediterranean Lake to Western commerce. So I read this article that you so timely posted today and it does appear that there is a gap between what must be described as the commencement of the dark age and the onslaught of Islam, that is, between 445 and 620 A.D.
Of course, we do not know if Western Europe would have recovered the splendor of the Western Roman Empire had it not been forced to contend with Islam.
Pasta Vandool?
...”Towards the end of the mid fifth century we see a shift in the diet of the local populations away from one rich in animal protein and imported wheat, olive oil, fish sauce and wine from North Africa, to something more akin to a ‘peasant diet’, made up of mainly plant proteins in things like potages and stews. They’re doing the same kind of manual labour and hard work, but were sustained by beans and lentils”
...
They turned into soy boys.
Dr O’Connell concludes, “Are food resources and diets shaped by political ruptures? In the case of Portus, we see that when Rome was rich everybody, from the local elite to the dockworkers, was doing fine nutritionally. Then this big political rupture happens and wheat and other foodstuffs have to come from somewhere else. When Rome is on the decline, the manual labourers, at least, are not doing as well as previously.”
...
So “trickle down economics” is a good thing.
Bump for later.
Even lower class Roman citizens living in Rome and its environs could enjoy what was considered luxury items thanks to the grain dole and like provided by the Roman state. Considering bread tended to represent a big proportion of income for most people the state subsiding that item freed up a lot of income for luxury items in this case meat. Most of these luxury food items would have been imported from throughout Rome’s Empire.
The Vandals conquered Rome's North Africa provinces cutting off Rome from those items. People had to go "local".