IF YOU visit a long, brightly-lit cafeteria in South Salt Lake, Utah, on a Sunday morning, you can hear a low babble of conversations, over steaming mugs, eggs and pastry, between people who have only just met but seem keen to share their experiences. In a typical conversation (reported with permission), a 45-year-old woman called Sally Benson chatted to Casey Rawlins, a man 11 years her junior, about a difficult move they had both made: leaving the Mormon faith. She explains that she “made the break” on the first day of 2013: “It was, like, my whole life so it’s hard to break out, you know…” Her new friend is sympathetic; he explains that he made a similar decision a few years earlier, even though most of his friends and family were Mormon. “You have to change your whole social group,” he recalls. These chats are not the result of random encounters. The cafeteria is a meeting place for "Postmormons and Friends", one of several groups with the stated aim of guiding people through the difficulties, whether practical, social or psychological, of ceasing to practise the Mormon religion. Those strains can be especially acute in Utah where the majority of people belong to the Church of Jesus Christ of Latter-day Saints (LDS).

By some measures the LDS church still has a demographic profile which other religious groups would envy. It claims to add members, both in the United States and worldwide, every single year, although the annual rate of increase that it reports has slowed significantly. Last year, it posted an increase of global membership of 1.7%, for a total of 15.6m, including 6.5m Americans. The yearly rate of increase in the global total has come down from around 5% in the mid-1980s. Mormons can point to the fact that their share of the United States population remained steady at around 1.6% between 2007 and 2014 while the total share of self-described Christians tumbled from 78% to 71%.

The Mormon church gains members through intensive missionary activity and as a result of its conservative family structure; a high proportion of Mormons are married and raising children in a devout atmosphere. But clearly, quite a lot of those children eventually leave; a recent survey of the American religious landscape found that only 64% of the respondents who had been raised in the Mormon creed still adhered to it.

Rick Philipps, a religious sociologist, has studied the particular problems that arise in Utah, the heartland of Mormonism. In some urban areas, the population used to be so heavily Mormon that people had the same peer group in religous and non-religious settings. Partners in a neighbourhood or commmunity group were also likely to be fellow members of a "ward" or local church unit. This created huge and decisive pressure for members to stay within the fold. But now that these neighbourhoods have become more religiously mixed, "the salience of this [all-Mormon] religious subculture is waning," he told Religion News Service. That makes leaving a conceivable choice, in a way that it hardly was before; but it is still difficult enough.

Leaving the church involves more than just renouncing a set of beliefs, says Martha Bradley-Evans, Dean of Undergraduate Studies at the University of Utah who specialises in the LDS church. It also involves saying goodbye to a support network on which most members are heavily reliant. “The context of a Mormon ward is incredibly important in the life of a member,” she says.

And every so often, something happens which turns the flow of departures from a slow trickle to a larger torrent. There was one such event last year when Mormon leaders tightened both the style and substance of their line on same-sex relationships, especially gay marriage; people entering such unions were threatened with discipline and possibly excommunication. During the weekend following that news, at least 100 church members gathered in a park and formally began resignation procedures. Since then more than 10,000 have left for similiar reasons, says John Dehlin, a psychologist who leads a podcast called Mormon Stories. In some of these cases, he says, "people’s lives really get messed up."

Officially, the process of leaving starts with the submission of a letter requesting that one's name be removed from the church roster. But such letters can be passed around between various church bodies, and they can lead to unannounced phone calls and home visits from church members. This can take months. Mormons are heavily involved in each other’s lives, and when one member wants to resign, fellow believers will weigh in and urge their brother or sister not to forfeit a ticket to heaven, says Mark Naugle, an attorney in Salt Lake City who has helped thousands resign. He assists with drafting resignation letters, designed to ensure that his clients can make a relatively clean break without any official backlash. But no break is completely painless.

On the other hand, some still-practising Mormons insist they continue to behave charitably towards lapsed brothers and sisters. "I have always maintained positive relationships with friends who have left the church," says Marcus Jessop, who lives in Orem, Utah. A lifelong Mormon aged 34, he acknowledges that some of his coreligionists might not be so warm towards the fallen; but his belief was in "striving to love everyone" regardless of their faith choices.

As any religion-watcher will tell you, Americans of his age and below see religion (like every other aspect of personal and economic behaviour) as a matter of individual rather than group choice. The Mormons, like all religous communities, will have to adjust to that era.