How soybeans took over the American diet – without anyone noticing

Soybeans were not originally a major crop in the United States. They were first brought to North America in 1764 by an English sailor named Samuel Bowen, who had collected them in China. Initially, soybeans were treated as a curiosity and used only for small-scale experiments, such as producing soy sauce. However, their role changed dramatically around 1900 when U.S. Department of Agriculture researchers, including Charles Piper and William Morse, began studying and distributing soybean varieties from China. They identified traits that made soybeans suitable for cultivation in the U.S., leading to increased farming. By 2026, U.S. farmers are projected to produce a record 4.52 billion bushels of soybeans, which translates to roughly 800 pounds of soybeans for every American, even though most people do not realize they are consuming soy products.

Originally, soybeans were primarily grown as forage and livestock feed. The transformation of soybeans into a dietary staple began in the 1910s with the rise of industrial processing methods. These methods involved crushing soybeans to extract oil, typically using chemicals to separate the bean into two main products: protein-rich meal for animal feed and oil for various uses. Soybean oil became particularly valuable due to its low cost, neutral flavor, and versatility. By 2008, soybean oil accounted for approximately 80% of the 18 billion pounds of edible oils used annually in the U.S. It became a common ingredient in foods like salad dressings, mayonnaise, baked goods, and fried foods, as well as in non-food products such as paints and soaps.

Industrialist Henry Ford was a major advocate for soybeans, seeing them as a bridge between agriculture and industry. In the 1930s, Ford’s company incorporated soybeans into automobile manufacturing, using soybean oil in paints and soybean meal in plastic parts. By 1935, Ford was using roughly one bushel of soybeans in the production of every automobile. In 1941, he unveiled a prototype car made from 14 soy-derived plastic panels. Ford also promoted soybeans as a food source, hosting a soybean luncheon in 1934 featuring dishes like soybean purée, cheese, bread, and even apple pie with a soybean crust. Despite his enthusiasm, Ford’s soybean cuisine did not gain widespread popularity. However, his industrial applications laid the groundwork for soybeans' later role in the American diet.

World War II played a key role in making soybeans a dietary staple in the U.S. During the war, the country faced shortages of imported fats and oils, prompting processors to turn to domestic vegetable oils, particularly soybean oil. After the war, the demand for protein-rich soybean meal surged due to booming livestock production. This also led to an oversupply of soybean oil, which processors needed to find new markets for. Food manufacturers discovered that soybean oil was ideal for processed foods because of its low cost and neutral taste. Between 1942 and 1972, butter consumption in the U.S. dropped from 16.4 to 5 pounds per person, while margarine consumption rose from 2.9 to 11.1 pounds per person, largely due to the availability of cheap soybean oil.

Soybeans became a ubiquitous part of the American diet not because people actively chose to eat them, but because they were incorporated into foods in ways that were not immediately obvious. Soybean oil is now found in salad dressings, mayonnaise, baked goods, infant formula, snacks, and fried foods. Soy lecithin, a byproduct of soybean oil processing, is used as an emulsifier in products like chocolate and bread. Soy protein is added to energy bars, breakfast cereals, and canned soups to fortify them. The versatility of soybeans allowed them to be used in a wide range of products, from livestock feed to human food, making them a hidden but essential part of the American diet.