Purcell's paper "The Way We Used to Eat: Diet, Community, and History at Rome" is the place to start. While the rural plebs may have had a more complicated diet, the urban plebs got their protein from the same source as most of their nutrients: emmerdale porridge. Emmer wheat has a fairly high protein content, and when supplemented with beans (chickpeas are particularly well attested in the texts) can provide sufficient protein. As Harrison points out in a piece on Clodius, however, we must imagine--and crunching what numbers we have supports--that the urban plebs were, while not starving, chronically malnourished. I disagree with Harrison's belief that caloric intake was insufficient, because the numbers do not agree, but vitamins, minerals, and nutrients like protein were, to the best of our knowledge, only barely sufficient most of the time, if sufficient at all. There has recently been an interest in the availability of fresh produce and animal products in the city. Mignone, for example, suggests that many urban dwellers may have had window gardens, an idea that has been raised by others. The evidence, however, is quite slim, effectively a single line of Martial. Much better attested is the impact of market days. Ever ninth day in the city was a market day, and the immediate hinterland a day's journey out from the city appears to have been dominated by vegetable and meat production, rather than crop staples as elsewhere. The suggestion from this would be that fresh produce, and the supplementary nutrients thay they could provide, might actually have been somewhat more plentiful than Purcell and the orthodox view suggest