What happens next is no surprise: Jack and Elizabeth grow up. By 2014, the teen spirit that buoyed them deep into their 20s has transformed into a fog of insecurity and regret. They have a child they don’t understand, careers that leave them wanting and a relationship drained of intimacy. Where they once shared everything, they now keep much hidden. “They were always aware of what the other was doing and saying,” Hill writes. “Less so what the other was thinking.” Jack and Elizabeth have become — God and Courtney Love forgive them — normal.

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But have they really? The beauty of Hill’s second novel is that every character is at least a little strange and no one is unworthy of sympathy. Even Brandie, the judgmental school mom who causes Elizabeth deep aggravation, is “like a compassionate and generous and bighearted Bond villain.” Few recent novels harbor as much love for humanity as this one does. It spares everyone.

“Wellness” is not some naive, crunchy-granola midlife crisis novel. Hill’s follow-up to “The Nix,” his acclaimed 2016 debut, is a clear-eyed look at the difficulty to live honestly in a world where authenticity may be the most challenged idea of all.

With ‘The Nix,’ Nathan Hill announces himself as a major new comic novelist

People are never more ridiculous than when they’re assigning meaning to events and experiences they don’t comprehend. In “Wellness,” that covers just about everything. Hill has paid close attention to America’s obsession with diet, spirituality and the self, and he has fun illustrating our willingness to delude ourselves and others about such matters. The novel is studded with terms and phrases that will be familiar to anyone who has sat through a TED Talk or a mindfulness seminar at work: “gut health,” “biohacking,” “engagement,” “next-level self.” Hill has an ear for speech that says nothing. “What you have to understand,” one woman tells Elizabeth, “is that the universe responds to symbolic action.”

Hill rejects mockery. He gets the need to believe life is not a series of random accidents. Elizabeth, who works at a government-funded lab called the Institute for Placebo Studies, considers magical thinking “a pretty rational and sane response to systemic collapse: If nobody else was going to protect you, you had to do the job yourself. You had to believe in something. You had to find, somewhere, hope.”

As Jack and Elizabeth attempt to diagnose their marital pain, they entertain remedies their younger selves might have scorned. Jack falls prey to a digital fitness program that supposedly monitors everything from UV exposure to optimism. Elizabeth, meanwhile, befriends Kate, a 25-year-old polyamory advocate who calls marriage a “useless heuristic” and, in one of the book’s most distressing episodes, persuades Elizabeth and Jack to meet her and her husband at a clandestine swingers’ club. They escape without having unfastened a single button but with their relationship in extreme jeopardy.

‘Confidence’ skewers the rich in a most satisfying, clever way

The couple’s lingering Gen-X attitudes — Jack worries that he’s devolved into a “boring vanilla toxic untalented gentrifier” — leave them vulnerable to pseudoscience but also rescue them from it. In one delicious scene, Elizabeth attends a gathering of Brandie’s “Community Corps,” neighborhood morality snoops who claim to be following the example of Mother Teresa, citing the Catholic saint’s reported argument that “pro-peace” is a more aspirational term than “anti-war.” The group’s ranks include a man who believes reality is constructed from psychic holograms. “The key is to keep persisting inside your fantasy until the fantasy becomes a fact,” he says. Elizabeth leaves the meeting early.

At almost 600 pages, “Wellness” has an insistent pull. Hill’s writing can be gorgeous, especially in passages devoted to Jack’s tragic childhood on a Kansas prairie, a landscape with “no dimension, nothing in relief, very little visual drama, no contours for the light to sculpt, none of the things that create what we might traditionally call a view.” The author stumbles just once, with an overlong chapter on social media algorithms that has little new to say on the subject but nonetheless ends with a gut punch of a plot development.

During a conversation about how people view themselves, Elizabeth’s mentor and former professor tells her, “Alas, the truth is of very low importance, psychologically speaking. We’re really very silly creatures.” To Elizabeth, the man “seemed greatly entertained by this, even sort of jolly.” The same can be said of Hill.

Jake Cline is a writer and editor in Miami.