'I felt disgusted with myself'

says Lisa Longhurst, 30 from Crawley, West Sussex

This time I'd really outdone myself. I'd scoffed an entire cake – and I didn't feel sick, even after all that icing. It was only later that I felt the shame wash over me. But that night I still tucked into fish and chips.

Overeating was just normal behaviour for me. When I was 16 I spent all my pocket money on crisps, chocolate and sweets. I felt no one understood me and secretly binged in my room. 'You need to watch your weight, love, 'Mum said as she noticed the pounds pile on. At 19, I was size 26, with a huge stomach and wobbly thighs. I told myself I didn't care but deep down I did.

Two years later in 2003, I met Dan and soon fell pregnant. Sadly we split and I moved back home to Mum's. After my son Ellis was born my weight soared – and I stopped getting on the scales. My clothes were getting tighter and I was squeezing my 5ft 5in frame into a size 30. I knew I had to do something about my weight, but it was hard. Ellis suffered colic and I spent hours trying to settle him, and ate whatever I could get my hands on – normally huge sandwiches laden with cheese and mayonnaise.

As the years passed I felt disgusted with myself, yet I didn't change my eating habits. 'All my friends think you're fat,' Ellis said in April last year when I fetched him from school. 'What?' I cried, shocked. I didn't want him to be embarrassed by my size, so I went to see my GP. I was 23 stone. 'I'd like a gastric bypass,' I said. I knew it would take something drastic for me to lose weight as I'd never stick to a diet. 'It's a big step,' my GP replied. 'But I'll refer you.' Luckily I was accepted by my NHS hospital and the operation was scheduled for January.

At Christmas I piled my plate high with potatoes, stuffing, Yorkshire puddings and extra turkey, I ate until I thought I was going to burst. I knew it was the last time I'd be able to. After the operation all I ate was soup, yoghurts and crackers, but I felt full. Big meals were a thing of the past. Amazingly, I didn't miss fatty foods, even If I watched Ellis eat a chocolate bar. The sacrifice was worth it. In just 10 months I've lost 10st 11lb and I'm a size 12. My confidence has gone through the roof and I love being able to wear skinny jeans. 'You look wonderful,' Mum told me. Ellis, nine, is impressed with his new mummy too. I feel like a different person and wish I'd done it sooner. I know that in 2012 the new me is here to stay.