The website Medievalists.net has an interesting article which challenges the oft-expressed view that meat in the medieval period was very much for the rich rather than the commonality of people. Using statistical evidence gleaned from taxation records and household accounts in Catalonia and England the author suggests that considerably more meat was consumed on a daily basis in the fifteenth century ( and by implication earlier on ) than would be normative today.
I suppose that the quality was more variable than today, and before high meat yielding animals were selectively bred from the eighteenth century, the weight per animal would be lower. The fat content might have been higher, or the meat more scraggy, but I am sure medieval cooks knew how to be creative.
It is a further corrective or emendation to the frequently expressed idea that medieval life was drab and always at subsistence level for the overwhelming majority of the population.
The article can be read at Beefing up Medieval Europeans: Meat Consumption