Janet Thomson was out shopping with the young woman who was her fitness club’s Slimmer of The Year. Janet was helping the woman buy a new outfit for a photoshoot to publicise her achievement.

“This girl had lost eight stone,” remembers Janet, “and I told her to choose something she liked. She went off into the shop – and came back with a big, black, baggy tent of a dress. I said to her ’You’re not fat any more’, but she hadn’t changed how she felt about herself.”

It was an epiphany moment for Janet who, the next day, enrolled on a clinical hypnotherapy course to supplement the diet and fitness training she had been offering to women for a number of years. “It made me realise I had to include some sort of psychological element that would stop them going back,” says Janet. “You have to change your mind first and your body will catch up.”

To that end, Janet is now trained and qualified in Neuro-linguistic Programming (NLP), Thought Field Therapy, or tapping, and clinical hypnotherapy, as well as having a masters degree in nutrition and exercise science, and has put her findings together in her latest book, Think More Eat Less.

“The theory behind it is that if you don’t change how you think about food then you can’t change your body,” says Janet, who runs classes and workshops in Borehamwood. “A diet is a very short-term fix – it often results in you eating more when you come out of it. What’s been missing is a do-able programme that trains you to change how you think or feel. At the moment, most of us think ’When I’ve lost the weight I’ll do this or I’ll do that and then I’ll feel good about myself’ – that’s completely the wrong way of doing it.”

How did we all come to get it so wrong?

“It’s learned behaviour,” Janet explains. “When you’re a baby mum says ’Stop crying and you’ll get a rusk’ or encouraging a toddler to cross the room for the reward of a biscuit. The intentions are good but it can be really harmful in later life, and everything you’re taught as a toddler – food to deal with emotional upset – is reinforced in the media as you grow up.

“It’s such a strong association it can stay in place until something stronger comes along to replace it. We have to understand that everything we do is to get a feeling, an emotion. ‘I’m bored, I want to feel something else – what can I do? I’ll eat’.

“It’s about making different connections, deleting some connections and putting different ones in their place.”

The book includes a range of techniques that Janet has proven over the years – NLP, tapping, self-hypnosis and a number of her own hybrid exercises – and follows Mabel, a woman who followed Janet’s techniques to great success, via excerpts from her diary at the end of every chapter.

“If you’ve tried dieting and failed, if you’ve ever had that feeling ’I just want someone to sort my head out’, then this is for you. It won’t just help you with your weight, it will start having positive effects in other areas of your life as well.”

  • Janet is running a one-day Think More Eat Less workshop at Charters Health Club, YMCA, Charter Place, Watford on Sunday, March 17. Details: www.powertochange.me.uk. Her book Think More East Less is out now.