It was an appearance The Late Late Show in the early 1970s that first introduced the Irish public to Agnes McCourt, founder of Unislim. At the time slimming clubs were virtually unheard of here, but McCourt's interview with Gay Byrne beamed the concept into hundreds of thousands of homes and the business took off overnight.

Forty-four years later Unislim is a household name with 12 full-time staff and 100 leaders countrywide running up to 300 classes weekly catering for around 60,000 people a year.

The slimming club market here is dominated by Unislim (the only wholly Irish-owned company), WeightWatchers which originated in the US and the UK-based Slimming World.

"It's flattering that people talk about us in the same breath. They are big international brands and we're not. Nevertheless we have competed successfully against them for years while maintaining a strong market share," says Fiona Gratzer, who took over running Unislim when her mother retired three years ago.

Agnes McCourt started Unislim because she wanted to lose weight but could find few supports to help her. The best her GP could offer were slimming pills.

“My mother was far more interested in combining healthy eating and exercise to lose weight and this has been the underlying philosophy of Unislim since. It’s not about deprivation and dieting. It’s about eating well and being active,” says Gratzer who has worked for Unislim for over 20 years.

Initially McCourt ran all of the classes herself but, as demand for new groups grew, it became obvious that would have to change. McCourt and her late husband Brian developed Unislim as a franchise and began training leaders to run their own groups. This system is still used today and Unislim typically recruits leaders from within its own membership.

While groups are still the backbone of the company’s operations, it has also diversified into the corporate sector and runs employee wellness and healthy eating programmes in the workplace.

Roughly 80 per cent of Unislim members are female but there has been a rise in the number of men attending and there are men-only groups. “When Unislim began, 70 per cent of the population was classified as being of a healthy weight. Now 70 per cent of the population are either overweight or obese,” Gratzer says.

The McCourts are from Northern Ireland and originally set up Unislim there before relocating to Dundalk in 1979.

“It was much easier to break into the Dublin market from Dundalk and that really helped the business grow quickly,” Gratzer says. “Unislim was the first of its kind in Ireland and the UK but it wasn’t long before others followed and they keep coming.

“In some ways it’s good because it helps expand the market and introduce slimming clubs to younger generations and we benefit indirectly. We’ve always traded in a competitive environment and you have to work even harder when you’re the older, more established brand,” Gratzer says.

“You need a USP [unique selling point] to keep people coming and we have a reputation for friendliness and for putting a lot of effort into creating a supportive and fun environment that takes the sting out of losing weight,” she adds.

“We’re also very proactive in the technology area and have invested in excess of €200,000 over the last 18 months alone to engage more actively with our members. . . .”

Unislim now uses swipe cards to speed up weigh-ins and has created a hub where members can access recipes, connect with others to share their stories and success, and upload their exercise outcomes from electronic fitness bands.

In 2016 Unislim will launch its own wearable band that will measure activities such as fitness, sleep and exercise to give members a 360-degree view of their health.

Under Gratzer’s direction Unislim has also begun to spread its wings into new areas. The company has just launched a food range that will sell under the Gorge Us label.

“The aim was to create tasty healthy food not diet products,” Gratzer says. “Our first product is pure and simple oven chips and we will also introduce meals, soups, snack bars and yogurts that tick all of the nutritional boxes when it comes to no hidden salt, sugar or other additives.”

Manufacture of the food products has been sub-contracted and Gratzer estimates the investment in Gorge Us to be around €200,000.

Unislim has recently established its first group in the UK. “My ambition is not to be the biggest. It’s to be the best,” Gratzer says. “We know that establishing credibility in the UK will take time. But Unislim in Ireland has grown successfully organically and there is no reason why the same thing can’t happen over there.”

Unislim has thrived during the recession. “We actually do better when times are tough,” Gratzer says. “As a business we have grown during the downturn with a growth rate of around 10 per cent per annum over the last two years.”