Good genes? How can Trump eat a lot of fast food, exercise little and be healthy?

Jayne O'Donnell | USA TODAY

Show Caption Hide Caption Trump's doctor says the president is healthy, has no cognitive issues Trump's doctor says the president is 'healthy,' has no cognitive issues. The White House physician, said the 71-year-old Trump stands 6 feet, 3 inches tall and weighs 239 pounds. Video provided by AFP

The White House physician maintained President Trump is in "excellent health" Tuesday, despite what a new book describes as his strong attraction to fast food, including cheeseburgers in bed.

Ronny Jackson, the White House physician, said the 71-year-old Trump stands 6 feet, 3 inches tall and weighs 239 pounds. He also said Trump has "above average" exercise capacity, even though he doesn't exercise beyond golf.

That height and weight gives Trump a body mass index (BMI) of 29.9 which places him in the overweight category on the verge of obesity, defined as a BMI of 30 or greater.

So how is he so healthy?

"Incredible genes, i just assume," said Jackson, who said he told Trump that if he ate better and exercised for the last 20 years he "might live to be 200."

While Trump's may be the dream diet of a teenage boy, it's a nightmare for those trying to model or message that healthy eating — and exercise — are the key to good health. Tyson's Corner, Va. internal medicine doctor Sam Pappas faced that dilemma the same afternoon Jackson was explaining Trump's health data to the press. A 50-something male patient described his "very Trumpesque" approach to diet and exercise during a follow up to his own physical as if it was okay.

Pappas, who frequently performs physicals for government and military personnel, said he had to remind his also-stocky, muscular man that unlike the teetotalling Trump "you like to have your wine." As with his own patient, Pappas said he would encourage lower Trump to eat lower carbohydrate diet with more healthy fats.

Indeed, Jackson is going to work with Trump and a nutritionist on the president's diet which will emphasize lower carbs and fats.

"There are 'good' genes, but what research has shown us is that more than genes, more than health care, more than social circumstances, behaviors are the leading cause of premature death," says Bernadette Melnyk, a professor and dean of Ohio State University's college of nursing and the university's chief wellness officer. "And there's good evidence behind that."

After all, one's genes can only do so much.

"Some gene variants are slightly more efficient at detoxifying harmful chemicals in the liver, which leads to a slightly decreased cancer risk," says Maureen Murphy, a cancer geneticist with the Wistar Institute in Philadelphia. "But I don’t think good genetics trumps — I mean beats — bad lifestyle."

Trump's supporters emphasize that the fact he's never been a smoker or drinker is key to his good health, but most experts say diet and exercise are still critical to good health and longevity.

Still, Pappas says Trump's triglycerides level (the amount of fat in the blood) of 129 is good, his blood pressure of 122/74 is "very good" and his blood glucose level of 89 is "a very good marker" as it's under 90. Above 90 is pre-diabetes.

Pappas also says government physicals, including Trump's, don't have as much data as he would like, such as waist measurement which would be a better indicator of problems than BMI for someone with a muscular build like Trump. Jackson said the physical did not include body measurements.

Trump has stated openly that exercise is overrated, even going so far as to say that it can create more problems than it cures.

‘‘All my friends who work out all the time, they’re going for knee replacements, hip replacements — they’re a disaster,’’ Trump said in a September 2015 New York Times Magazine article.

Jackson says he will come up with an exercise program for Trump that doesn't put his joints at risk.

Former House Speaker Newt Gingrich and media company owner Chris Ruddy told USA TODAY in earlier interviews that Trump is genetically high energy and benefits from his cleaner living habits. Jackson agreed Tuesday.

Smoking is "about the worst" thing you can do for your health and "drinking isn't too far behind," says Murphy. But excess weight is a "terrible risk factor for poor health." Diet and exercise are "roughly equal" in importance to not smoking or drinking, says Murphy.

While fast food and sweets are hardly what she'd like to see the commander in chief eating, Melnyk and physician Bruce Lee of John Hopkins University's Global Obesity Prevention Center advocate the 80/20 rule, or that if you adhere to a well balanced and healthy diet for about 80% of what you eat, the rest can be less healthy foods.

"Everyone's a human being and if they try to stick to a very strict diet, it's difficult for anyone to be able to maintain that," says Lee, who is also a professor at Johns Hopkins' Bloomberg School of Public Health.

More:

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Trump doesn't get any exercise beyond golfing with a cart that Jackson or others know of. Asked if that's moderate to vigorous activity as described by the federal government, Lee says "not necessarily." Walking back and forth to a cart and swinging a club, don't bring golf anywhere close to sports such as basketball or swimming, Lee says, but he does note it "gets you out in nature."

Playing golf while riding a cart burns only about half as many calories than walking, or an average of 411 calories for nine holes, according to a study by Neal Wolkendoff of the Colorado Center for Health and Sport Science.

Even if Trump has had good health until his early 70s, that doesn't mean his lifestyle will lead to longevity beyond what he's already experienced or for the typical 71-year-old, which is what Jackson predicted he would at least achieve.

If your gene variants have helped prevent disease, it's "not because of lifestyle — you’ve been lucky," says Murphy. "Luck is a huge part and it might not last."