I read this comic: xkcd: The Race (Part 3), and felt the urge to shout "Cite your references!". Is it true? Does the average human consume their body weight in food in just over a month?
According to a study by the clinical nutrition centre of Addenbrokes Hospital, Cambridge, UK measuring the food consumed by a random sample of the population of a Cambridge village:
The average weight of food eaten per day (excluding drinks) was 1277 g
That would give a month's weight of food as around 38kg. That's less than the average weight of a person, by a factor of around 2. I would expect an average British person to be eating significantly more than the average for people worldwide. They could be eating less than the average for the US, but I doubt it is by a factor of 2.
So no the claim is not strictly true. But an error by a factor of two is actually pretty good for a web comic, and might be just a case of artistic license