First no shaving, then no booze, now no meat or milk
In the beginning, there was Movember. Then there was Stoptober. Now prepare yourself for Veganuary.
Those who have overindulged this festive period may be tempted to turn vegan for January. If so, they will not be alone. Organisers of Veganuary, now in its third year, predict that tens of thousands of people will take part this month - of whom around half will stay vegan.
About 3,000 people participated in the first Veganuary. Last year, the figure rose to 12,800. But eschewing meat, fish and dairy products is now becoming increasingly fashionable thanks to a number of high-profile advocates.
Famous names who have tried vegan diets in the past include Bill Clinton and actor Anne Hathaway. Committed vegans include Brad Pitt, Ellie Goulding and Gwyneth Paltrow. And Kat Von D - an American tattoo artist and model - caused the Veganuary website to crash earlier this year when she encouraged people to register.
Among the celebrities taking part this month are comedians Romesh Ranganathan and Sara Pascoe. Actor Peter Egan of Downton Abbey fame and designer Vivienne Westwood have also signed up.
Organisers of the event claim the surge in support for veganism reflects a growing awareness that it can help alleviate the world's food crisis.
Rearing animals for consumption and dairy production produces significantly more carbon dioxide than plant-based food. In addition, animal farming is the leading producer of methane gas, a major contributor to global warming. However, organisers say that concern for animals was still the primary motivation for people going vegan.
"We ask about motivation when people sign up to Veganuary and, for the past two years, animals are the primary reason by a large majority, with health coming second, and the environment third," said Clea Grady, marketing manager of Veganuary.
"There is an increasing awareness and concern at how we treat, use and abuse animals, and this is growing. Anecdotally, we know that, for whatever reason an individual approaches veganism, the lines begin to blur once education has taken place."
The business world is also waking up to the vegan market. Companies such as VBites, Violife and Fry's market products such as vegan cheese, ice-cream, "fish" fingers, burgers, sausages, schnitzels and "chicken" nuggets.
Some nutritionists argue that humans cannot derive all the minerals and vitamins they need from a pure vegan diet. Both Clinton and Hathaway famously turned their backs on veganism. "I just didn't feel good or healthy," Hathaway once explained.
However, Grady said veganism could provide a balanced diet. "All it requires is a little knowledge and guidance, and that's what Veganuary specialises in," she said.
"The Health and Nutrition sections of Veganuary.com were co-authored by a GP and a qualified nutritionist, so we are confident in the information we provide."