Peanuts Are Not Actually Nuts

Despite its name and its place in the snack aisle, the peanut is a botanical imposter. It belongs to the legume family, Fabaceae, making it a close relative of lentils, soybeans, and peas. The confusion is understandable, but the key difference lies in how they grow. True nuts, like pecans and walnuts, grow on trees. The peanut plant, however, is a marvel of nature. It flowers above ground, but after fertilization, the flower's stalk elongates and burrows into the soil where the fruit (Review)—the peanut pod—develops entirely underground. This unusual process is known as geocarpy.

This botanical distinction has been largely ignored in the kitchen and in nutritional science. Originally cultivated in South America thousands of years ago, the peanut's high fat and protein content gave it a nutritional profile remarkably similar to that of tree nuts. When it was introduced to the rest of the world, its culinary uses mirrored those of true nuts, from being roasted and salted to being ground into a butter. So, while botanists classify it as a legume, chefs and nutritionists continue to group it with nuts, creating a delicious and enduring case of mistaken identity.