There has been much debate about da Vinci’s model for the Mona Lisa but I am not aware of a similar debate over the model for Michaelangelo’s David. However, it has often been suggested that Michaelangelo was homosexual. This leads us to wonder about whether the model for David was upper class or lower class. If he was an aristocratic youth, his diet could have been what is now called ‘neolithic’ (ie meat and fruit). If lower class, it is more likely to have been that of a medieval peasant (ie starch relieved by herbs, spices and fat). Dave’s diet is more predictable and can be characterised as ‘Macdonalds’. He probably has far, far too much High-fructose corn syrup (HFCS) and can be expected to fall to CHD or diabetes or a stroke.

“However spices were very expensive for a long time there
was no known all water route to the West. So instead the spices had to change
hands as much as 5 or 6 times. Indian spice farmers would grow the spices. They
would then sell them to Arabs who would travel across the land by camel to the
west edge off the Mediterranean where they would in turn sell them to the European merchants.

This long line of middlemen came to an end, though, in 1498 when the Portuguese explorer Vasco Da Gama discovered the first all water route to India. The discovery of an all water route to India allowed European Merchants to deal directly with Indian spice dealers. This made spices cheaper throughout all of Europe. However, the elimination of Arab middlemen created
much uproar throughout the Middle East. Although most men did not have to worry
about them, the trek for men passing through these areas became very dangerous,
and attacks on caravans became much more common.

Explorers brought back countless new foods and spices from territories that they found. Columbus was the first European other than the Norsemen to make it to the New World. When he
came back he brought with him: Potatoes, tomatoes, corn, and squash from the
north, and peppers, and beans from the Caribbean and South America. Among
other commonly traded goods from the New World were cocoa, sugar, and tobacco.”
[ http://www.thehistoryconnection.com/Renaissance-Food.html ]

It seems that David’s diet is based on locally available produce and overland trade while Dave’s diet benefits from the rise of sea trade in the age of maritime exploration.

No, no and no.
David’s patrons, or perhaps his owner if he was a slave (there were many slaves in renaissance Italy), will have eaten too much sugar but it seems most unlikely that a high-born youth would work as a nude model so he probably lived off fresh meat and fresh vegetables. Sea fish, like sardines, were a luxury, though they would have been good for his Omega 3 intake.