They used a beef broth in the oil before. Some vegetarian nutjob found out about it and threw a fit and that was that.
Beef tallow.
Founded in 1940, McDonald's initially used 93% beef fat tallow for their French fries in an effort to save money, according to a piece on the origins of the favored fast food item published by Atlas Obscura. The money-saving decision resulted in a meaty flavor that unexpectedly gave the fries their signature taste so singularly unique that McDonald's eventually trademarked their menu item as their "World Famous Fries," according to their website. This remained the case until 1985, but things changed years later after the launch of a campaign designed to wage war against the fast food empire.
Per Atlas Obscura, it all began when a multi-millionaire businessman named Phil Sokolof had a heart attack at 43 in 1966. Following his recovery, Sokolof attributed the cardiac event to his diet, so he began researching the correlation between high-fat foods and heart health. This prompted him to found an organization he named the National Heart Savers Association, with the aim of spotlighting Mcdonald's — and, to be fair, other fast food restaurants — with claims that their beloved, beef tallow-laden fries, along with other high cholesterol foods found on their menu, contributed to heart disease (via The New York Times).
After spending at least $15 million campaigning against McDonald's for more than two decades, Sokolof got the attention of consumers, per Atlas Obscura. In 1990, McDonald's eventually responded to the pressure by replacing their beef tallow will vegetable oil. But the story didn't end there.
Consumers thought McDonald's new fries were vegetarian-friendly
Now for the scandal. As Atlas Obscura explains it, some consumers welcomed the ingredient change. Particularly, vegans and vegetarians, who had previously been unable to consume a fry or two due to McDonald's use of beef tallow, assumed they could now enjoy the popular fast food side. That is, or so they thought.
Yes, beef fat tallow was eliminated from the cooking oil, but since the change affected the flavor that many other consumers loved, the franchise found itself on shaky ground. Stocks in the company fell, prompting McDonald's to take action once again (via Atlas Obscura). They attempted to mimic the original taste by adding "natural flavors" to the fries — natural beef flavors, which were added during the pre-shipment potato processing, per the Wall Street Journal.
In another misstep, the company demurred from publicly announcing the ingredient change. The discovery left vegans and vegetarians outraged, along with those who came from religious backgrounds like Hinduism which forbade the consumption of beef tallow. Three later sued McDonald's in 2001 for misleading them. As the Wall Street Journal reported at the time, McDonald's countered that they never said their fries were vegetarian. Either way, they eventually settled with a $10 million donation to religious and vegetarian groups and an apology from the fast food giant. Nowadays, if you check their "World Famous Fries" webpage, you'll see "Natural Beef Flavor" clearly listed in their "allergen information" section.
Read More:
The McDonald's Fries Scandal You've Forgotten About - The Daily Meal