Exhausted from working 15-hour days running her own marketing agency in London, Jo Miller’s evenings would consist of a cocktail of takeaways, Ubers and impulse purchases. “I’d end up spending £100 at Waitrose, grabbing a takeaway or going out for dinner as I didn’t have the energy to cook. At the train station I’d feel the need to buy something, so I’d end up spending loads at Oliver Bonas. It was all instant gratification.”

That was two years ago. Since then, Miller has closed the business, moved to Margate and launched a new career as a sound therapist, using a combination of alchemy crystal singing bowls and her voice to relax clients. And with the life shift, she has dramatically focused her time and money on one particular area: wellness.

Instead of unhealthy takeaways and excessive shopping, the 42-year-old spends £18,000 a year on her wellbeing. This includes £3,200 a year on a transpersonal psychotherapist, £3,000 on retreats, and £1,000 on supplements, probiotics and vitamins. She also receives a weekly organic fruit and vegetable box, has a CrossFit membership and enjoys regular treatments such as massages.

Jo Miller with her alchemy crystal singing bowls in Margate

For Miller, wellness is about “people reconnecting and being comfortable in their mind and spirit level. Before, people were distracting themselves through consumerism.” Now, Miller says, she has “completely switched” her expenditure. “Wellness is the new currency,” she adds.

But at £18,000 a year, how can Miller afford it? For her, it’s about refocusing her life choices. “I spend very little on anything else. I don’t have a mortgage – and I have lodgers to support the money I make from working as a sound therapist.”

Miller is far from the only person spending their hard-earned cash on wellness, which can range from spin classes and meditation sessions to organic food and kombucha drinks. In fact, the global market for health and wellness reached £532bn in 2016, and is expected to grow to £632bn by 2021, according to Euromonitor International.

Yoga at the Soul Circus festival, soundtracked by Faithless star Maxi Jazz

Wellness encapsulates everything from superfood-charged smoothies to sleeping aids and yoga mats. Festivals, which used to be primarily focused on music, are also placing more emphasis on wellness.

This year’s Womad devoted two acres to its spa and wellbeing area, and featured 40 vendors and therapists offering everything from meditation with a Buddhist monk to shamanic healing. Wellness festivals such as Soul Circus in the Cotswolds, which costs up to £199, are also sprouting up, giving festivalgoers the chance to tap into everything from meditation and kids’ yoga classes to nutrition demos and sober morning raves. “I wanted to create a balanced event that left you feeling rejuvenated and inspired rather than hungover and unhealthy,” says Soul Circus founder Ella Wroath.

James Veal, 42, a project manager working in central government, describes his wellness journey as a “slow burn for the best part of a decade” before he seriously ramped it up two years ago. “I started feeling my age a little – I felt stiff when exercising, and I was reaching that midpoint where I thought I have a whole other half of my life left and I want to make sure it is in better quality,” he says.

James Veal takes fitness seriously – including climbing

He invested in a Vitamix blender (from £299) so he could make smoothies from nuts, leafy greens and a micro algae supplement, which sets him back about £100 for two months’ supply. He now spends about £30 a week buying organic food from the local farmers’ market plus £50 on an Abel & Cole delivery.

He also has plans to visit a wellness retreat abroad. “I’m fortunate as I have some disposable income, so it doesn’t feel like a huge sacrifice,” says Veal, who estimates he spends about £250 a month on his wellbeing. However, his health kick means the Londoner spends less eating out, as he avoids food that may contain pesticides, and he has cut back on alcohol. The result, although more costly, has had benefits. “I feel amazing. It’s honestly been a revelation to me – I sleep much better,” he says. “I used to have occasional periods of insomnia, but I’ve lost weight, my skin is clearer, and people comment that my skin is glowing.”

But is this level of wellness only attainable to a few middle class high earners with the income – and some might say credulity – to afford the high spending? Gwyneth Paltrow’s wellbeing business Goop, which has been under fire for endorsing treatments such as vaginal steaming and inserting jade eggs, stocks aromatherapy oil for $85 (£66).

Demonstrating the Vitamix food blender, which costs from £299 and upwards. Photograph: Alamy

“The trend has developed a reputation for being quite expensive and elitist,” says Sarah Housley, senior editor of lifestyle at trend forecaster WGSN. “At the more luxury end of the market, wellness also became a way for people to show off their wealth more subtly than by buying an expensive handbag or car – instead, they could go to exclusive yoga classes and drink expensive juices – a trend that we call ‘wellthness’.”

Gina Clarke, 31, a freelance PR executive, says she moved to a more wellness-fuelled lifestyle in 2016 after she visited her parents and saw they had invested in a juice blender. “After a quick Google and realising the health benefits, I was soon juicing up my own smoothies,” she says. “I used to have a green juice for breakfast and then something avocado or egg-based for lunch.”

However, she soon found keeping up the lifestyle was too much to bear. “I’ve gone to my fair share of yoga retreats but found it so hard to recreate at home. My yoga ball lies deflated – a little like me. I soon realised the search for the Instagram lifestyle was getting a bit too tiring alongside work and a family life. Now my stress levels have come down considerably.”

Gina Clarke says wellness can be an affordable lifestyle. Photograph: Scott Miller/Wiltshire Photography

Despite the pricey fitness studios and £10 green smoothies, Housley says wellness can be affordable: “You can drink more water for free, you can do yoga or pilates from a YouTube video at home.”

Veal is the first to admit that he undertakes wellness activities that don’t cost money: he meditates twice a day for 20 minutes and runs several times a week.

Housley says there is a move to more conscious conversation around wellness, with a focus on making it more accessible and inclusive. “People are increasingly trying to find a balance, shifting their priorities from self-care to community care, and there’s a growing backlash towards brand partnerships that exclude certain people or don’t truly support the community,” she adds.

Wellness, including reflexology, has become more of a focus at festivals such as Womad. Photograph: Alamy

Despite the myriad of trends that crop up in wellness, whether it’s acai bowls or forest bathing, Professor Helen Stokes-Lampard, chair of the Royal College of GPs, believes the essence of what keeps us healthy remains the same.

“These include not smoking, only drinking alcohol in moderation, getting enough sleep, eating a nutritious, well-balanced diet and taking regular exercise,” she says. She warns against fads that claim to improve health and wellbeing.

“They might be well-intentioned, but they are often not supported by robust clinical evidence. Trends can be useful for raising awareness of new or changing health issues and for getting people involved in improving their own health, but by definition they might not be around for long. That’s why it’s essential that as a society we all work together to encourage each other to lead healthier lifestyles, not just for a few months of the year, but permanently.”