New research reveals link between weight loss groups and increased mental toughness

"I know I’d be 19 stone now if I hadn’t joined Slimming World. I’ve lost 7 stone and turned my life around!" Kirsty Muir

Kirsty Muir, 32, from Alloa, Clackmannanshire used to sit in the supermarket car park and secretly eat donuts, now she’s lost 7st and is a regular at the gym

Kirsty’s story backs up new research from the University of Lincoln which reveals the link between weight loss groups and increased mental toughness

Kirsty Muir 000

“I joined Slimming World three years ago in January 2019 weighing 18st 5lbs. I had problems with my health, I was a size 20, over 18 stone, far too self-conscious to go clothes shopping and I hadn’t even had my 30th birthday. I knew I had to change, I wanted to become a better version of myself and joining Slimming World was the best decision I’ve ever made. I’ve even joined a gym which is incredible to me – it’s something I never thought I’d be able to do. I know I wouldn’t be the person I am now without the support I get from going to group each week.” says Kirsty.

“Before I lost weight, I was diagnosed with hidradenitis suppurativa, a painful condition which caused abscesses and scarring on the skin under my arms. I was referred to hospital and advised that if I lost weight, that would help manage the problem. Now I’ve lost 7 stone, the condition is easily managed, it’s so much better and I can’t believe I’d suffered for so long.”

“If I think back to my life before joining Slimming World, I was a completely different person. When you’re a bigger girl, people assume you’re the biggest personality in the room. This isn’t true. I appeared confident but deep inside I was very shy and hiding away. I also realised I was a secret eater as after each supermarket visit, I’d sit in the car park and eat all the treats I wanted to, from a couple of donuts to cakes, sweets, crisps, without anyone knowing. Then I’d have another treat when I got home. I was constantly clearing the car out, removing any evidence, and it was getting embarrassing.

“Now I never feel hungry! I love that I can have a treat too and I don’t have to cut everything out. With my husband David working shifts everything I used to make for his tea was quick and easy junk food – all shop bought pizzas, garlic bread and pre-made curries. We made nothing from scratch. Now, David and I eat the same main meals which helps a lot with my weight loss. He says too that since I joined Slimming World, he’s never felt so full. If we’re having chicken or fish, we make sure all the skin and fat are removed. Our spice rack is full and we always have tins of chopped tomatoes in the house. Our favourite meal is cottage pie and Teriyaki Salmon – all my life I didn’t think I liked salmon and now I love it! When we’re pushed for time, we enjoy the Slimming World food range at Iceland and add extra vegetables.

“I’ve gone from being a size 20 to a size 10 and I dress for my age now rather than wearing frumpy clothes to divert attention elsewhere. I also now walk a lot more. I have two dogs and I take them for walks three times a day. Before this would have seemed like a chore, now I love walking them and seeing how far I can go.

“Losing 7st has changed my life and saved my life! Since joining Slimming World and losing weight, my confidence has grown so much. I truly believe if I hadn’t made the decision to join my local Slimming World group when I did, I’d be over 19 stone by now with even more health problems.”

Dr Jacquie Lavin, Head of Research and Scientific Affairs at Slimming World
Kirsty’s story shows the depth of understanding about the psychology of weight loss we have at Slimming World. It’s been at the heart of our method for more than five decades.
Dr Jacquie Lavin, Head of Research and Scientific Affairs at Slimming World
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Dr Jacquie Lavin, Head of Research and Scientific Affairs, says: “In our groups we share techniques to empower and enable members to make their own behaviour changes through a variety of methods, including setting goals, making new decisions, developing skills to overcome barriers by facing, and seeking out challenges and taking back control, which are all linked to the principles of improving mental toughness. By encouraging our members to try new foods, transform old, unhealthy habits and change their perception of food and activity, we create an environment for our members to challenge themselves on their own timescales.

Professor Peter Clough[3], Technical Director at AQR International, developed the 4Cs model of mental toughness: challenge, commitment, confidence and control. The study found that Slimming World members had increased scores in all of the 4Cs during the six months they participated in the study.

Dr Elizabeth Stamp, Lecturer at Loughborough University
Looking at the 4Cs model it’s understandable that Slimming World members showed an increase in mental toughness scores. The multi-level support to make lifestyle changes which the group provides is specifically designed to help members increase their commitment to their weight loss and the changes needed to ensure they achieve them. It supports them to feel in control of their choices and behaviours and feel more confident in their ability to make the changes even in situations where their commitment and motivation would otherwise be challenged (for example eating out, travelling, staying away from home, socialising etc).
Dr Elizabeth Stamp, Lecturer at Loughborough University
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Dr Elizabeth Stamp, who studied the role of mental toughness on health-related lifestyle behaviour change when completing her PhD at the University of Lincoln, says: “Helping members think about the challenges, make plans for when things may get in the way and develop strategies for these times, are all ways in which the group supports members to stick to their plans and successfully lose weight each week.”

Bill Usher runs the Saturday morning Alloa Elim Church Slimming World group in Clackmannanshire and is Kirsty’s Slimming World Consultant. He says: “I’m proud of Kirsty as I have not only seen her transform physically but in her lifestyle too, making healthy lifelong changes. She is such an inspiration to me and the other members in group, she’s always so encouraging to everyone. Kirsty’s an amazing member, a true success story!”


Group: Kirsty attends the Alloa Elim Church Slimming World group in Clackmannanshire which is run by Consultant Bill Usher on Saturday mornings. For more information or to find your nearest group, visit slimmingworld.co.uk.

Kirsty Muir

Starting weight: 18st 5lbs

Weight lost: 7st

Current weight: 11st 5lb


Breakfast: On a weekday I would grab a bacon, sausage or black pudding bread roll from the local shop followed by a latte with two sugars. At the weekend I would have a fried full English breakfast or sugary cereal

Lunch: Fish and chips or a sandwich from the office canteen, with a bar of chocolate, packet of crisps and sugary drink

Dinner: A lot of processed foods, shop-bought pizza or curry and garlic bread

Snacks: cakes, crisps, bars of chocolate, sweets


Breakfast: Weetabix with blueberries and honey or overnight oats

Lunch: Left over Slimming World meal from dinner the night before, or a baked potato and beans. Juice with no added sugar and fresh coffee with sweetener

Dinner: Slimming World cottage pie or Teriyaki Salmon with lots of vegetables and/or salad

Snacks: high fibre bar, fruit, home-made hummus with carrots to dip, low-fat crisps

[3] Professor Peter Clough is writer and co-writer of almost 50 articles and books on mental toughness, including 2002’s ground-breaking Developing Mental Toughness, a big-seller acknowledged as the definitive guide.

About Slimming World

Slimming World was founded by Margaret Miles-Bramwell OBE in Derbyshire in 1969 and has become the UK and Ireland’s leading weight loss organisation with more people choosing to attend a Slimming World group each week than any other weight loss programme. We support hundreds of thousands of people, both in our groups and online, to lose weight and to adopt new habits to stay slim for life.

Over the years our founding principles haven’t changed:

  • Our unique programme is based on a powerfully motivating support system called IMAGE (Individual Motivation and Group Experience) Therapy. Underpinned by a deep understanding of the psychology of overweight people, and incorporating the most effective sustainable behaviour change techniques, IMAGE Therapy is designed to inspire and motivate slimmers to make positive changes and to develop new, healthier habits around food and activity.
  • Food Optimising is our healthy eating plan, based on the liberating concept of Free Food. We encourage our members to fill up on those foods that are naturally lower in energy density (calories per gram) and also highly satisfying while limiting foods that are highest in fat and sugar and are less satisfying, so they lose weight without ever feeling hungry or deprived and without having to weigh, measure or count everything they eat.
  • Our activity programme, Body Magic, encourages members to become more active, more often in ways that they enjoy, until regular physical activity becomes an intrinsic part of daily routine.

Above all, at the heart of everything we do, lies our passion for treating every member with genuine care, empathy and respect.

We’re proud to work with the NHS, the Office for Health Improvement and Disparities (OHID), The Royal College of Midwives and others to help shape the future of weight management in the UK and Ireland. 

For further information please contact the Slimming World press office on email public.relations@slimmingworld.co.uk