The chain on Monday announced it had switched over to "tallow fries" at stores in Ohio, Colorado, Florida, Texas and Oklahoma, adding that by March 1 fries at all locations would be "RFK'd."

"Congratulations @SteaknShake for being the first national fast-food chain to begin the transition away from seed oils," Kennedy wrote Thursday responding to the news.

Congratulations @SteaknShake for being the first national fast-food chain to begin the transition away from seed oils. Thanks for leadership in the crusade to Make America Healthy Again. https://t.co/eEqF6No1bc

— Robert F. Kennedy Jr (@RobertKennedyJr) February 27, 2025

"Thanks for leadership in the crusade to Make America Healthy Again," he added.

Meanwhile, Children's Health Defense, the health-conscious non-profit formerly headed by Kennedy, weighed in asking the restaurant to also consider revamping other items on their menu.

Steak 'n Shake's transition from seed oils to tallow comes as Trump's brief stint working at a McDonald's in Pennsylvania inspired calls for the fast-food giant to bring back beef tallow frying oil.

President Donald Trump's HHS secretary has previously slammed seed oils for contributing to America's illness epidemic.

"Seed oils are one of the most unhealthy ingredients that we have in foods," Kennedy told Fox & Friends last year, ahead of the election. "And seed oils, the reason they're in the foods is because they're heavily subsidized. They're very, very cheap, but they are associated with all kinds of very, very serious illnesses, including body-wide inflammation, which affects all of our health."