A former White House physician who memorably said Donald Trump might have lived to 200 if he had improved his junk-food heavy diet has confessed to sneaking cauliflower into the president’s mashed potatoes.

“The exercise stuff never took off as much as I wanted it to,” Dr Ronny Jackson told the New York Times. “But we were working on his diet.”

In terms familiar to harassed parents of toddlers worldwide, Jackson said that work included “making the ice cream less accessible” and “putting cauliflower into the mashed potatoes”.

The retired navy rear admiral, 52, left the White House in December and is now running for Congress in Texas.

He served three presidents but his star rose under Trump after he told the press in January 2018 the heavy-set property magnate, then 71, had “incredibly good genes” and “if he had a healthier diet over the last 20 years, he might live to be 200 years old”.

The Times reported that Trump, now 73, had gained four pounds when his next physical rolled round.

Trump nominated Jackson to lead the Department of Veterans Affairs but the doctor withdrew amid controversy about his qualifications for the role and alleged behavior in the White House. He denied accusations including drunkenness and questionable dispensing practices.

Speaking to the Times, Jackson said he did not regret missing the chance to join Trump’s cabinet. He also said he had not called in favors from Trump in his campaign in Texas’s 13th district, a huge and safely Republican seat which contains the cities of Amarillo and Wichita Falls.

“He had so much on his plate,” he said.