Health and Human Services Secretary Robert F. Kennedy Jr. thanked fast food chain Steak 'n Shake for discontinuing its use of vegetable oil to make french fries, the New York Post reported.

The burger joint now uses beef tallow instead, a change it made on March 1, the chain announced and promoted on social media.

"The customers are raving about it. Steak 'n Shake has been great. We're very grateful to them for RFKing the french fries," Kennedy told Fox News on Monday.

Kennedy blamed seed oils as a catalyst for chronic disease in the U.S.

"Seed oil is one of the components of processed foods, and all the science indicates that ultra-processed foods are the principal culprit in this extraordinary explosion — the epidemic we have of chronic disease," he said.

Kennedy said he prefers incentives over outright bans of seed oils and signaled that other chains, including Popeyes, Outback Steakhouse, Sweetgreen, and Buffalo Wild Wings have switched or are in the process of moving away from seed oils, according to the Post.

"We want to do everything that we can to incentivize these companies to be transparent, to switch over from ultra-processed food, and to be part of this movement to make America healthier," he said.

• RFK Jr. Moves to Tighten Loophole on Food Chemicals
• RFK Jr. Issues Artificial Dye Ultimatum to Food Companies