Lewis's piece is a puff. Then again, he does tell us interesting stuff about the president – including his bedside reading

There are lots of "fancy that!" facts in Michael Lewis's balloon-sized Vanity Fair profile of Obama, which reads, in parts, less like journalism than a kind of fan fiction.

("I gazed up to find Obama staring down at me …" "I feel a little creepy being here," I said. "Why don't I get out of your hair?" He laughed. "C'mon," he said …" etc.)

Anyway: Obama goes to bed at 1am and gets up at 7am. Michelle goes to bed at 10pm. There are doors in the floor of Air Force One to accommodate a president's coffin, should the need arise. Obama junked Bush's ornamental china ("I'm not a dish guy") when he moved into the West Wing and replaced it with "original applications for several famous patents and patent models", including "Samuel Morse's 1849 model for the first telegraph".

He also had a rug made, interwoven with inspirational quotes not detailed in the piece, which makes one wonder. "Smile and the world smiles with you?" "You don't have to be crazy to work here, but it helps!"? Perhaps the White House redacted them, like the name of the movie that made Obama cry.

The whole piece is reminiscent of Martin Amis's 2007 profile of Tony Blair in the Guardian, in which he applied a novelist's eye to the prime minister's last few months in office, and annoyed a lot of political hacks. (Political hacks are always annoyed when a fancy-pants novelist – here's Amis, describing a car journey with Blair: "the crouched policemen, in their day-glo yellow strip, buzz past like purposeful hornets to liberate the road ahead" – shambles across their territory, chucking out metaphors and behaving as if he is the first civilian with language skills ever to have encountered a motorcade.)

To add insult to injury in the Lewis piece, it transpired that Vanity Fair gave quote approval to the White House, a measure usually reserved for low-stakes Hollywood puff pieces, and a condition that the big beasts tell themselves they would never have agreed to – although, as Glenn Greenwald points out, a kind of undeclared quote approval among suckier elements of the White House press corps makes formal agreement unnecessary.

In this case, judging by the moony tone of the piece, Obama was never in any danger of Trojan Horse tactics. (One of Lewis's first questions on entering the White House is: "When people come here, are they nervous?")

Beyond a certain point, all of this is moot, however, since the aim of the profile clearly wasn't to grill the president on policy or political philosophy so much as to illuminate something less tangible – what it is like, existentially, to do his job. Here, Lewis harvests some interesting stuff.

"You need to focus your decision-making energy." [Obama says]. "You need to routinize yourself. You can't be going through the day distracted by trivia." The self-discipline he believes is required to do the job well comes at a high price. "You can't wander around," he said.

"It's much harder to be surprised. You don't have those moments of serendipity. You don't bump into a friend in a restaurant you haven't seen in years. The loss of anonymity and the loss of surprise is an unnatural state. You adapt to it, but you don't get used to it – at least I don't."

And:

"Nothing comes to my desk that is perfectly solvable. Otherwise, someone else would have solved it. So you wind up dealing with probabilities. Any given decision you make you'll wind up with a 30 to 40% chance that it isn't going to work. You have to own that and feel comfortable with the way you made the decision. You can't be paralyzed by the fact that it might not work out."

And:

"The first night you sleep in the White House, you're thinking, All right. I'm in the White House. And I'm sleeping here." He laughed. "There's a time in the middle of the night when you just kind of startle awake. There's a little bit of a sense of absurdity. There is such an element of randomness in who gets this job. What am I here for? Why am I walking around the Lincoln Bedroom? That doesn't last long. A week into it you're on the job."

If you don't exercise, says Obama, you're finished; and Lewis duly trails him to a basketball game, where the president "smiles when he misses". However stage-managed, this human stuff still offers a fascinating glimpse into the mental and emotional endurance test of being a man without peers.

And so, where does the president turn for comfort? He watches the sports channel ESPN. He hangs out with the "best friend", Marty, whom he knew before he was famous. And he reads. On top of a pile of paperwork in Obama's study, reports Lewis, is Julian Barnes's Booker Prize winning novel, The Sense of an Ending, a delicately angled choice: a literary hit but not so obvious it looks focus-grouped; international in scope and an example of the sophisticated, self-analysing sensibility used by Obama's critics to paint him as elitist.

Having the president of the United States read your novel is the ultimate test of the principle that good writing makes every reader think it's about them. In this case, that inclusionary principle washes back over the president. Barnes's exquisitely tempered novel is a long way from the White House – the protagonist is a Brit who has failed at most things – and yet there it is, the common strand, the arc of empathy: the story of a man going back over his life, weighing the choices he made and their long-range consequences, wondering, at the end of the day, if he did the right thing.