Editor’s Note: Michael D’Antonio is the author of the book “Never Enough: Donald Trump and the Pursuit of Success” (St. Martin’s Press). The opinions expressed in this commentary are his.

(CNN) —  

Cast your mind back to the 1970s. A young Czech-born model named Ivana joins her husband-to-be at the touristy restaurant called Tavern on the Green on the west side of New York’s Central Park.

The waiter, bending to hear the orders at a table crowed with a group hosted by the father of the clan, hears one person after another say: “I’ll have the steak.”

When Ivana’s turn came, she opened her mouth to speak and was interrupted by the paterfamilias. “She’ll have the steak,” said Fred Trump Sr., real estate magnate and father of a future president of the United States.

“No, I’ll have the fish,” she says.

“No, she’ll have the steak.”

In the showdown, Ivana didn’t budge. She got the fish and thus established she was her own person, with her own preferences. Donald Trump, the man who would become first her husband and then POTUS, had the steak. He would order it countless times in the future. And when he wasn’t choking down on sirloin, it would be fried chicken or hamburgers.

Fast-forward 40-plus years and Ivana is no longer Mrs. Trump, and she’s sharing her dining room story with me to explain how domineering Fred Trump could be and how she won his respect. This conversation, which was part of an interview for the biography I wrote about her ex-husband, also illustrated the President’s approach to diet and fitness.

As everyone who has paid attention knows, President Trump has never been a health nut. His diet is famously poor and his approach to exercise begins and ends with golf played from a riding cart.

When I interviewed Trump, we met in his home, which was atop Trump Tower, and then, after the tape recorder was switched off, we went downstairs to his office before saying goodbye. Each time, he walked me through the gym that was on a floor of the building, so he could show off one of the towers amenities. He repeated this tour the way he repeated stories, and each time he would say: “I’m told it’s a good gym. I don’t know. I don’t use it.”

During the campaign for the White House, candidate Trump showed he had ample energy, criss-crossing the country and giving impassioned speeches. However, he was enabled by a staff of handlers, his private jet and a carefully-planned schedule.

And though people around him insisted he had a young man’s vigor, so many misrepresentations came out of his mouth – and the mouths of his aides – that no one could know what was true.

As with so many things about Trump, Americans were asked to ignore what they saw with their own eyes – a substantially overweight man of 70 dining on fried chicken and burgers – and accept the sales pitch.

In the meantime, his side did everything they could to suggest that opponent Hillary Clinton was hiding one health problem or another and physically unfit for office. In August, the candidate himself said Clinton lacked the “physical stamina” to serve.

Looking at the two, no one with eyes to see would imagine Trump was healthier.

Further dissonance arose when Trump and Clinton issued medical reports. Hers was comparable in detail to those released by Barack Obama and his opponents in 2008 and 2012. Her physician, an internist, noted hypothyroidism but declared her in good condition.

Trump’s medical report was filed by a gastroenterologist, hardly a general medicine expert, who in Trumpian fashion declared he would be the “healthiest individual ever elected to the presidency,” though he offered little real information.

This week, the world learned that Trump’s doctor was either more salesman than physician, or he didn’t perform the kind of tests and analysis that would permit his glowing report.

The White House, to its credit, announced that the President has a form of heart disease, which, barring changes that might occur with diet and exercise, put him at moderate risk of a heart attack in three to five years.

News of the heart condition comes amid concerns – contradicted by the White House physician – that Trump could suffer from a cognitive problem. (Turns out his intemperate behavior and statements are a matter of character and attitude.)

I for one always thought the problem with Trump was his heart, not his mind. But I was speaking symbolically, not medically. As we now know, the trouble – if truly cardiac and if his longstanding habits are any indicators to go by – he will struggle to change in ways that could help him.

I think it is worth noting that the President’s temperament, which is one type of heart problem, and his health concern, which is another, may have the same antecedent.

Fred Trump was a demanding, impatient man who likely laid the foundation for Donald Trump’s own bullying tendencies. He also set the dietary template, insisting everyone should have the steak.

Considering the son’s problems today, one can’t help but wish Fred had been a kinder, gentler father who taught his boy it was okay to order the fish.