The protester was seen with the severed head outside Vegfest at the Brighton centre, where he was filmed biting off small bits of the carcass.
It appears the stunt mostly served to put people off meat rather than the other way round.
The protester, who calls himself Sv3rige on YouTube but who is also known as Gatis, said he ate chunks of the raw head in protest against veganism because the diet “is human cruelty”.
He told Sky News: “We did it - it was eight of us - because veganism is malnutrition and you can't get over 15 nutrients from plants and some of us are ex-vegans who got sick because of it.”
Eventually the police arrived and reportedly gave the man and two other people a warning, and they left.
While nibbling at the pig’s head, the man was surrounded by counter protesters from an animal rights group holding signs saying, “Meat is murder” and “It’s not food it’s violence”.
Tim Barford, Vegfest UK manager, told the Brighton and Hove Independent: “We knew about the planned protest and were expecting 30 protestors – three turned up, which was slightly sad for them and reminiscent of a Nigel Farage march.
“But they proceeded to upset kids and members of the public, and with that in mind, the police arrived, gave them a warning and sent them packing.”
He added: “What was interesting was that we had meat eating members of the public saying that this revolting spectacle had encouraged them to give up eating meat – so it seems the anti vegan protest actually encouraged people to go vegan.”
According to the Brighton Argus, activists from Direct Action Everywhere challenged the man.
“A lot of everyday people walking past were also repulsed by the sight of a pig’s head which is interesting as most of these people eat pigs as well,” a spokesperson for the group said.
“It goes to show what we already know, that people don’t like seeing the faces of the animals they eat.
“Eating animals is eating a product of torture and death. Why is animal abuse so normalised when it’s in a burger but shocking when we see the being behind the burger?”
Last year members of Direct Action Everywhere stormed into a Brighton restaurant in protest at it serving meat to customers.
Eating raw pork can lead to humans contracting the trichinosis infection, if the meat is infected with parasitic worms.