U.S. farmers will produce a record-breaking harvest of 4.52 billion bushels of soybeans in 2026, according to projections from the U.S. Department of Agriculture. At 60 pounds to the bushel, that is roughly 800 pounds of soybeans for every American.

Most people don’t think of themselves as soybean consumers. Few sit down to a plate of soybeans, but soy is hiding in plain sight throughout the American diet. Soybean oil appears in salad dressings, mayonnaise, baked goods, infant formula, snacks and fried foods; soy lecithin emulsifies chocolate and bread; and soy protein fortifies energy bars, breakfast cereals and canned soup.

As an environmental historian who studies agriculture and food, I seek to understand a peculiar transformation: How did a plant that most Americans barely ate a century ago become a ubiquitous food ingredient without people noticing?