Seed oils rose to mainstream popularity in a series of waves, starting in 1911 with the launch of Crisco and accelerating dramatically after World War II. By the 1960s, official dietary guidelines were actively encouraging Americans to replace butter and lard with vegetable oils, cementing seed oils as a kitchen staple. But the full story stretches back more than a century, driven by a mix of food science, wartime shortages, government policy, and shifting nutrition advice.
The First Seed Oil: Cottonseed and Crisco
Before the 20th century, Americans cooked almost exclusively with animal fats like lard, tallow, and butter. Cottonseed oil existed, but it was largely treated as an industrial byproduct of cotton production. That changed in 1911, when Procter & Gamble introduced Crisco, a shortening made from partially hydrogenated cottonseed oil. The hydrogenation process, first patented by German chemist Wilhelm Normann in 1903, turned liquid plant oils into a solid fat that looked and behaved like lard, making it suitable for baking and frying.
Crisco’s marketing was aggressive and effective. Procter & Gamble positioned it as a modern, cleaner alternative to animal fat, and it caught on quickly. This was the first time a seed oil product reached mass-market popularity in the United States.
Margarine and the World War II Boost
By the 1930s, margarine manufacturers had shifted from using animal-based fats to domestically produced vegetable oils, partially hydrogenated into a spreadable solid. But margarine still faced an uphill battle. Many states had laws restricting its sale, including bans on adding yellow coloring to make it resemble butter. Dairy lobbies were powerful, and margarine was widely seen as an inferior substitute.
World War II changed that almost overnight. Butter was rationed, and consumers and food processors turned to margarine out of necessity. After the war ended, many of the old legal restrictions on margarine were relaxed. Some consumers had simply gotten used to the taste, and price made the switch easy to justify: in 1946, margarine cost about 23 cents per pound compared to 71 cents for butter. The combination of familiarity, affordability, and loosened regulations gave seed-oil-based margarine a permanent foothold in American kitchens.
The 1960s: Official Nutrition Advice Tips the Scale
The single biggest accelerant for seed oil consumption was the shift in dietary guidelines during the early 1960s. In 1961, the American Heart Association issued its first formal recommendation to substitute vegetable oils and polyunsaturated fats for saturated fat. This guidance was influenced heavily by research linking saturated fat intake to higher cholesterol levels and heart disease risk. Ancel Keys’ Seven Countries Study, which examined diet and heart disease across different populations, provided much of the intellectual framework, showing strong correlations between saturated fat consumption and coronary heart disease deaths.
The AHA’s recommendation carried enormous weight. It shaped government nutrition policy, school lunch programs, hospital menus, and food industry reformulation for decades. Seed oils like soybean, corn, and safflower oil were suddenly not just affordable alternatives to butter and lard. They were the “healthy” choice, endorsed by the country’s most prominent heart health organization. Consumption of vegetable oils climbed steadily from that point forward.
Farm Policy and the Price Advantage
Government agricultural policy played a quieter but equally important role. American farm subsidies trace back to the 1920s, when overproduction from the World War I era crashed crop prices. Programs evolved over the following decades, consistently supporting commodity crops like soybeans and corn. These subsidies kept the raw materials for seed oils artificially cheap.
Soybean oil, in particular, benefited from this dynamic. Soybeans were already grown in huge volumes for animal feed and protein meal; the oil was essentially a profitable byproduct. The 2002 Farm Bill reinforced commodity crop subsidies after a brief attempt to phase them out in 1996. The result was that seed oils remained far cheaper than animal fats or olive oil, making them the default choice for food manufacturers, restaurants, and home cooks on a budget.
How Big Seed Oils Are Today
The scale of modern seed oil production is staggering. Global oilseed production is forecast to reach nearly 692 million metric tons for the 2025/26 marketing year. Soybeans alone account for a record 426.8 million metric tons of that total. Rapeseed (the source of canola oil) is projected at 89.6 million metric tons, sunflower seed at 56.2 million, and palm oil production at 80.4 million metric tons. These oils are in virtually every packaged food, from salad dressings and chips to bread and frozen meals.
Soybean oil is the dominant seed oil in the American food supply. It overtook all other cooking fats decades ago, driven by its low cost and neutral flavor. If you eat processed or restaurant food in the U.S., you’re almost certainly consuming soybean oil regularly, whether you realize it or not.
The Recent Backlash
Starting around the mid-2010s and gaining significant traction by the early 2020s, a vocal anti-seed-oil movement emerged online. Critics focus primarily on linoleic acid, an omega-6 fatty acid that is the predominant fat in most seed oils. Their core arguments center on a few biochemical concerns: linoleic acid is prone to oxidation, which can generate reactive compounds capable of damaging cells; it serves as a precursor to molecules that promote inflammation; and high intake may disrupt gut bacteria and intestinal barrier function.
Dietary intake of linoleic acid has risen markedly over the past century in industrialized countries, largely due to soybean oil. Some researchers have noted that this rise parallels increases in the incidence of several cancers starting in the mid-1900s, though a direct causal link has not been established. The debate is far from settled. Mainstream nutrition organizations still generally recommend unsaturated fats over saturated fats, while a growing number of researchers and health influencers argue that the specific type of unsaturated fat matters more than previously acknowledged.
What’s not debated is the timeline. Seed oils went from an industrial waste product in the late 1800s to the most consumed cooking fat on Earth in roughly a century, propelled by food technology, wartime necessity, dietary guidelines, and agricultural economics working in the same direction.