Donald Trump at a Knicks game at Madison Square Garden in New York in 2007. REUTERS/Ray Stubblebine

Lots of fast food. Almost no sleep. And practically no exercise, aside from the occasional cart-supported round of golf.

This is a routine that a doctor wouldn't advise for a 20-year-old, yet it's the standard for the routine-loving President Donald Trump, according to Axios' "Trump 101" series, which notes that the 70-year-old is the oldest president to ever enter office.

On the campaign trail, the "three staples" of Trump's diet were Domino's, KFC, and McDonald's (Big Macs on silver platters), an aide told Axios, the new news website. That love for fast food is largely because of its consistency and the idea that fast-food companies maintain a standard of hygiene, according to an interview Trump conducted with Anderson Cooper that was cited in The New York Times.

Still, Axios reports that in the White House, Trump is more likely to favor well-done steaks, crab, and shrimp and the occasional side salad or vegetable to go along with that hunk of red meat (cooked until gray).

Regular consumption of red meat significantly raises the risk of death, especially from cancer and heart disease, according to the National Institutes of Health — and that consumption is also strongly linked with increased risk for Type 2 diabetes.

From a nutritional perspective, the occasional steak is fine, but doctors recommend limiting consumption.

For a healthy diet, one should "eat plenty of vegetables and fruits; balance calories; don't eat too much junk food," according to Marion Nestle, the Paulette Goddard professor of nutrition, food studies, and public health at New York University.

As far as Trump's diet goes, it doesn't look as if he's getting much in the way of any of these categories, via either his main meals or his snacks, according to the aide. For snacks on his plane, the president reportedly relies on Lay's potato chips and Keebler Vienna Fingers.

As for exercise, standard guidelines say the average person needs at least 150 minutes of moderate activity each week. Exercise improves general health and heart health, reduces stress, boosts mental clarity, improves sleep, and more, which is probably why both Barack Obama and George W. Bush were dedicated to their fitness routines while they were president. Lack of activity isn't new for Trump, who said back in 1997 that he worked out "on occasion ... as little as possible."

As for sleep, Trump has said he needs only three or four hours a night. Most people need seven to nine hours of sleep, though about 1% of the population is able to get by on four to six hours. Most of the rest of us are as impaired as if we were drunk after several nights of short sleep, even though we usually can't tell.

The Axios story says Trump believes in genetic gifts that will keep him healthy (and he doesn't smoke or drink, though he's a big fan of Diet Coke, which he drinks throughout the day). Trump's father, Fred, lived to be 93 and had Alzheimer's for the last six years of his life, according to an obituary. Still, aging takes a physical and mental toll on everyone — most people who manage to stave off those effects do so with intense physical and mental exercise, along with sufficient sleep and adequate nutrition.

As for how it's working out for Trump, that remains to be seen. He reportedly takes a statin to lower cholesterol and takes the hair-loss-prevention drug finasteride (brand name Propecia). At a Dr. Oz interview, his height and weight were given as 6-foot-3 and 236 pounds, which would give him a BMI of 29.5 and put him firmly in the overweight category (earlier reports had put his weight at 267 pounds).

Trump is far from the only president to prefer an unhealthy diet — James K. Polk reportedly would request cornbread instead of eating from a banquet of French cuisine. And he may have some genetic traits that help him out a bit.

Still, from a health perspective, science suggests that if he wants to thrive, he should work on those eating, sleeping, and exercise habits.