Vegetarian meat substitutes weren’t always as easy to find in restaurants and supermarkets as they are today. But here's a fun fact you might not know: the religious men who invented the graham cracker and corn flakes also popularized veggie burgers in the United States, Ernie Smith writes for Atlas Obscura.

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Sylvester Graham and John Harvey Kellogg are often considered the founding fathers of vegetarianism in the United States and while their diets were partly driven by a desire for good health, it wasn’t necessarily out of respect for animals that they left meat off the menu. Rather, Graham and Kellogg were concerned that rich, meaty diets were making people sex-crazed and destroying their moral fiber.

In the 1830's, Sylvester Graham became one of America's first diet gurus. An evangelical minister from Massachusetts, Graham believed that people’s health and morals were being eroded by sexual desire brought on by fatty, flavorful, meat-based meals. To fight what he saw as the decaying morals of American society, Graham devised a diet of appropriately bland food to get to the core of the problem, Adee Braun writes for The Atlantic. The core of his diet? The eponymous cracker, which Graham designed as a meat substitute for his followers, the Grahamites. The original Graham cracker was nothing like the sweet, cinnamon-flavored component of the modern ‘smore, but instead was made from the blandest whole wheat flour he could find.

While Graham’s diet lost popularity after just a few years, one of his proteges was Dr. John Harvey Kellogg, one of the inventors of the cornflake. As well as being a fervent Grahamite well into the 1890’s, Kellogg was a Seventh-Day Adventist, a branch of Protestant Christianity that promotes a vegetarian diet among its followers. Kellogg became a health guru himself, opening a health resort in his home town of Battle Creek, Michigan where he advocated a lifestyle of vegetarianism and exercise for good health and moral fiber, Smith reports. It was at the Battle Creek Sanitarium where Kellogg and his younger brother, Will, accidentally invented breakfast cereal by leaving some boiled wheat lying around for a little too long. The moldy dough flaked perfectly and soon after, Will Kellogg began selling the cereal as Toasted Wheat Flakes.

The two Kelloggs fought bitterly over who owned the rights to wheat flakes for most of the rest of their lives. But while Will went off to hawk cereal, John started his own company focused solely on selling fake meats made from wheat gluten. Although seitan and tofu had been around for generations, John Harvey Kellogg’s meat substitutes inspired other Seventh-Day Adventists to experiment with making the fake meat look and taste more like the real thing, Smith writes.

While it would take until the 1960’s for vegetarianism to catch on with the larger public, these days about five percent of Americans identify as vegetarian, according to a 2013 Gallup poll. Thanks to Graham and Kellogg, vegetarians have no need to fear being left out in the cold during summer cookouts.