I remember when veganism was considered fanatical. Vegetarianism was one thing, but cutting out eggs and dairy seemed like a lofty excuse for an eating disorder, and the vegans themselves – in popular imagination, at least – were the nearest thing we had to zombies: pale, slow and always moaning.

Since then, of course, it has become become a lot easier to be eating green. Vegan cookbooks are in many non-vegan kitchens. Chipotle just added a tofu burrito to its US menu. According to Forbes, “high-end vegan” was one of the biggest food trends of 2013. Now I’m not a vegan, but the other day, it seemed like a good idea to buy a thing that makes “linguine” out of butternut squash.

As the world has become nicer to vegans, they have returned the favour. Friends at Christmas who invited vegans to their house were gratified when they brought their entire dinner with them. I’ve heard flexible veganism described as “90% vegan, 10% grateful for what’s on offer”.

All of this has made meatless living a more accessible lifestyle for people who don’t think of themselves as part of a diet movement per se. Naturally, the food education group Meatout is using this wave of pro-veganism to campaign this week for people to cut meat out of their diets for a day. Today (Thursday) is the annual dedicated Great American Meatout, during which participants are urged to rethink their diets for a single 24-hour period, after which they are encouraged to consider trying it for one day a week – or even a year. It’s healthier, more ethical and, they say, a good way to publicize the rather frightening reality that obesity is a bigger health problem in the US than smoking.

It’s also sensible marketing. One day a week without meat? That’s something most of us probably do anyway, without thinking. And Meatout, although branded as a vegan movement, pushes a meat-free diet – rather than the whole nine yards, with eggs and dairy and all the rest.

When it comes to outright veganism, the sticking point for most people is cake and cheese. And although the ethical and health reasons are unimpeachable, Meatout is fighting a recalcitrance which boils down to a simple question: why be alive at all? Why not sit in a bare room, listening to your own breath and anticipating your next serving of ancient grains, while wondering what else you can cut out of your life? To non-believers, there are few words more depressing in the English language than “vegan bakery”.

And vegan restaurants have a ways to go. They are still mimicking non-vegan food to entice the sceptics among us, and the ploy just doesn’t work. I don’t know about you, but I don’t want my artichoke to be described as an oyster and still get charged 15 bucks for it. There’s a posh vegan restaurant in downtown Manhattan wherein, halfway through the $80 tasting menu, you realize with rising panic that everything – everything - is made out of cashews.

At the cheaper end, there are the vegan restaurants where everything is brown and steaming and straight from the 70s, and although it’s sobering and still overpriced, at least you feel virtuous at the end of it all. Whereas eight courses of nut cheese just leaves you feeling sad and betrayed.

The lesson of these experiences for the half or quarter-vegans among us is, perhaps, to take the pragmatic approach: eat meat when you go out, and cut down at home. Like abstaining from booze through January, veganism is something people are now willing to try for a short period, which is what Al Gore did ... and then found that it stuck. Given how much food we throw out, and how guilty one feels chucking out-of-date meat away, it makes financial sense, too.

I was in Vancouver this week and for the first time in ages ate at McDonald’s. I used to like eating there quite often, at airports and train stations, until Jamie Oliver described the meat as “pink slime” and that was the end of that. But I was in a hurry, and it was there, and I couldn’t deal with the idea of eating my way through the foam mattress roll of a sandwich from Subway. It’s a mark of how much things have changed that it didn’t feel like a treat or indulgence; it felt, instead, like a small failure in the day.