RFK Jr. and Melania Trump are on a campaign to improve Donald Trump’s diet, sources tell Page Six.

Said a Trumpworld insider: “RFK Jr. and Melania are ‘ganging up’ on the President-elect to eat in a more heathy way. Think fewer Big Macs and less KFC, and more lean protein, salad and veggies for energy and to improve his over all well-being.”

But another Trump insider insisted: “Nonsense! Trump eats whatever he wants.”

The alleged move to improve Trump’s diet comes after Kennedy, 70, previously called the food consumed aboard Trump’s airplane, “Trump Force One,” “just poison.”

But Kennedy — who dropped his own presidential ambitions to endorse Trump and become a cabinet pick — was then spotted on Trump Force One himself sheepishly posing with a McDonald’s Big Mac and a Coke.

Trump watchers wondered whether the move to get Kennedy to pose with the fatty fast foods — in a pic that included a smiling Trump, Elon Musk and Donald Trump Jr. — was a way to epically troll his former politcal rival.

“They did it as a joke,” said yet another source. “RFK Jr. is all about healthy living and no processed foods. He hates fast food. He probably didn’t eat it.”

Kennedy has been tapped by Trump, 78, to lead the Department of Health and Human Services, and has taken aim at processed foods to get them out of school lunches. He has also called for a ban on hundreds of food additives and chemicals.

(Kennedy has also been seen dining at Mar-a-Lago at gala dinners where dishes look downright gut-busting.)

But our source said that the Big Mac joke wasn’t aimed at humiliating Kennedy, but to “own the libs.”

“They’re f–king with people,” said the insider. “The libs take everything so seriously, they’re melting down. Team Trump is just messing with them on everything. Trump is New York He likes to bust balls.”

Reps for Trump did not comment.

The first source said Melania, 54, is so on board with the plan to improve Trump’s diet, she’s even been… cooking!

“Melania has, on occasion, been cooking family dinners at Trump Tower for the president and their son, Barron,” the source claimed. “She’s also encouraging him to make healthier choices.”

The insider said that the former model, “Melania famously watches every bite she takes… She has also guided their son’s eating habits since he was a toddler. Mar-a-Lago members say they spot her heading to the spa, to work out and have regular skin care and hair treatments.”

Earlier this year we reported that some wondered if Trump — like seemingly every big name in Hollywood, including Oprah Winfrey — had turned to Ozempic or another weight loss drug to drop some pounds.

But a source told Page Six at the time that staying away from the Mar-a-Lago desserts at his Florida club along with help from his wife had done the trick.