And no, they're not the ones you'd expect.

While fad diets once were spread by word of mouth and late-night infomercial, social media has become a crucial tool in helping foodies and health nuts alike propel trendy diets into full-blown cultural phenomenons.

This year has been a prime example—Whole 30, the Ketogenic Diet, the Dukan diet, and countless others, have become their own hashtags on Instagram and populate endless threads on both Twitter and Reddit. But the diet that gets most people buzzing on social media isn't actually among those just named.

A team of researchers at Brandwatch, a data-driven analytics group, released their annual insight report into which diets have flooded the mentions and timelines of America's social feeds, focusing primarily on Twitter. Researchers paid particularly close attention to "influencers" (accounts with robust followings) to see which diets, trendy or not, have earned the most social clout among users.

The most popular diet on social media is —drumroll please—the vegan diet. Veganism was the most talked about diet on social platforms this year among social influencers, with more than 50 percent of all social media leaders mentioning the diet in some capacity. The hashtag #vegan on Instagram has more than 64 million posts alone.

Gluten-free diets were the second most mentioned diet across platforms, which was closely followed by vegetarian diets in third place.

Thinking about going vegan in your own kitchen? Get help:

Brandwatch turned to Instagram and Reddit to learn more about why veganism earned more attention that other buzzy diets, but they couldn't define a singular explanation as to why the vegan diet was the most talked about among users. They did, however, identify that vegans have quite a vibrant online community.

Credit: Getty: BSIP / Contributor

While they were researching diets with social clout, Brandwatch also put together a list of the top 25 foods that most engaged social media users this year. The top five most popular foods mentioned aren't exclusively vegan—chicken, chocolate, cheese, salad, and cake took the top spots respectively—but many of the foods on this list have vegan or vegetarian alternatives, which is a category that has seen unprecedented growth over the last year. Ice cream, eggs, butter, pizza, and fish, are all scattered throughout the top 25 (click here to view) and all have vegan alternatives.

As more and more people are experimenting with vegan and vegetarian alternatives, social media has become a place to "vet" these items before trying them. At Cooking Light, we're always keeping an eye on the online community and frequently covering viral products—keep up with us as we identify which vegan and vegetarian items sweep social media next.