The Romans weren’t always reclining at a table loaded with roasted ostriches, literally eating until they were sick. The 1,000-year and pan-European extent of Roman history takes in an enormous culinary range. Rome was a hierarchical society too, and the slave ate an enormously different diet from the master he served.
The most tangible evidence of the Roman diet is food and human waste excavated by archaeologists. The cities of Herculaneum and Pompeii (destroyed in the 79 AD eruption of Vesuvius) have left sewers and rubbish heaps packed with digested dietary evidence.