This quote is from "Drink: A Cultural History of Alcohol". I don't have a real reason to doubt it, I am just looking for sources that back this up or elaborate on it.
I know that in the 13th century ale price is capped at 1 penny for 2 gallons. Had ale prices significantly decreased by the end of the 14th century? If so, what were the reasons? Or perhaps bread and a big joint of meat are just cheaper than I am imagining?
I can't comment on the ale, though it sounds high from what I know of the time period. What I can tell you is that the "meanest workers" in the 14th century weren't buying big joints of meat every day. Meat was a rarity for medieval commoners. Remember, meat is hugely inefficient to produce because it takes a ton of grain to feed the animal. Especially before the days of cheap seed corn. Medieval commoners got most of their protein from beans and the like. Here is a source. It's course materials for a college class, not a published work, but she cites sources and is speaking directly to the diet of a 14th century peasant. As for ale, she says people would drink three pints a day.
You'll probably get more helpful responses if you specify the location you're thinking of.