WASHINGTON — It’s best to keep him away from Roundup.

In a surprising revelation, President Trump has expressed a curious belief in the cancer-fighting potential of diet soda, as explained by Dr. Mehmet Oz, the Administrator for the Centers for Medicare & Medicaid Services.

During meetings at the Oval Office, Trump, 79, has been known to flaunt his collection of sweets and use a special red button to summon a diet soda, according to Oz, 65. These meetings typically include Health and Human Services Secretary Robert F. Kennedy Jr. as well.

“Bobby and I generally attend these meetings together,” Oz shared during a conversation on Donald Trump Jr.’s podcast, “Triggered.”

“Then your dad brings out the diet soda, claiming it’s beneficial because, as he puts it, if it can kill grass when spilled, it must also kill cancer cells in the body.”

Contrary to Trump’s theory, diet soda is often criticized by health experts. Various studies have linked it to negative health effects such as weight gain and insulin resistance, potentially increasing the risk of developing Type 2 diabetes.

Kennedy, 72, and Oz have been top crusaders in the Make America Healthy Again movement, seeking to inspire Americans to steer clear of processed foods and improve their dietary habits.

But their attempts to push Trump to change his own diet have fallen flat.

“We were on Air Force One the other day, and I walk in there because he wants to talk about something, and he’s got an orange soft drink on his desk,” Oz recounted, referring to Fanta. “I said, ‘Are you kidding me.’”

“So he starts to sheepishly grin. He goes, ‘You know, this stuff is good for me, it kills cancer cells.’ And then he tells me, ‘It’s fresh squeezed, So how bad could it be for you?’”

Trump Jr. laughed at his father’s wild health theory, but credited him for being energetic for a near-octogenarian.

“I think even if he’s not going to adhere to a perfect diet himself, I think he wants people to at least have the knowledge,” the Trump scion said.

Oz suggested that Trump is healthy, harking back to the 2016 campaign cycle, when the TV doctor examined the future president.

“He was in perfect health. I mean his testosterone, quite frankly, was through the roof not taking any supplements,” Oz reflected.

The 47th president is well known for his quirky medical beliefs, reportedly theorizing that exercise can be unhealthy because people are born with a finite amount of energy — a view described as Trump’s “battery” theory.

He’s also a fan of fast food, having ordered McDonald’s, a restaurant he worked at for a day in 2024, to the White House on Modany via DoorDash.

Shortly after his 2024 victory, a beaming Trump posed next to a distraught-looking Kennedy and other allies with McDonald’s meals aboard his private plane.

“He has the constitution of a deity. I don’t know how he is alive,” RFK Jr. told “The Katie Miller Podcast” earlier this year about the president’s “unhinged” diet.