I'm an emotional overeater. There, I've admitted it. When I get stressed about something, such as a deadline at work, I reach for the nearest sugary treat, usually biscuits or chocolate, and shovel it into my mouth.

One time at university, during an intense, all-night essay crisis, I binged on an entire packet of Hobnobs one after another. Last week, however many years on, I carried on eating a biscuit even though I knew it was stale.

I know roughly why I do this - in psychological terms, it's called a Displacement Activity, something that puts off the inevitable.

And I'm not alone. Some 1.3 million of us in the UK are comfort eaters and it's become so common that in October last year, doctors in America gave it a new classification: binge eating disorder, putting it on a par with bulimia and anorexia.

In a world where obesity is now a major strain on medical resources, comfort eating, overeating or binge eating is a big issue.

Dr Jane McCartney, a chartered psychologist and author of Stop Overeating: The 28-day Plan To End Emotional Eating, knows only too well "the emotional pitfalls, the irritations and highs and lows" of trying - and failing - to lose weight.

She became a comfort eater in her early teens as a way of rebelling against her dad's draconian no-snacking rule.

"My dad made sure you finished your meals, and he went potty if you ate between them. I don't know if it was because of his experience during the war, he was an evacuee. But it was absolute agony because I was brought up in a guest house and we used to have nuts and crisps for all the guests.

"The moment I got that tiny little bit of freedom from my first job, I just ate all the things I wasn't allowed: chocolates, milkshakes and things like that. The more independent I got, the more I put on weight."

She says emotional eating is unique to everyone, but in the majority of her patients, it's connected to relationships "people are having, have had or don't have".

"It's often down to formative relationships with parents and siblings and poor current relationships with partners or family. Sometimes people are stressed, anxious and depressed because of the relationship they have with their own children."

Many emotional eaters will snack in secret, too embarrassed to be seen eating by others, and they can display very specific behaviours.

"You'll get people who will buy in two or three packets of biscuits and they buy very well-known branded biscuits because they know when they've eaten the whole packet, they can go down to the corner shop and replace them," Dr McCartney. "These are often people who think, 'I don't even like biscuits' and they certainly wouldn't eat biscuits or cakes in front of other people.

"There's a lot of secret eating that goes on, which then adds to the shame and guilt and humiliation about the eating, so these poor people seem to go round in massive circles all the time."

Personally, one of the problems I find is that whenever someone in the office makes me a cup of tea, I have a Pavlovian kind of response which immediately makes me want a biscuit to go with it. Dr McCartney calls this an "environmental trigger", which I need to be aware of.

"You have to be honest with yourself and have a dialogue with yourself. Because when we rush to the fridge or cupboard to get the cake or tin of biscuits, we're ignoring ourselves. We're ignoring the little voice that says, 'Hang on a second', and it's easy to do that because motivation to go for the high-fat and sugary stuff is really strong."

In her book and therapy sessions, Dr McCartney gets overeaters to think about the emotional chain of events that happens each time they're in a distressing situation, that leads them to overeat. The 'emotional trigger' can be something small like thinking a colleague has just blanked you.

Then she encourages people to take backward steps to identify the emotions they're experiencing, both in the immediate short-term and longer-term ones (eg problems at home), rather than automatically - and unthinkingly - reaching for the nearest morsel of food to make them feel better.

Dr McCartney advises me to take 10 minutes after something triggers me to eat, to see if the emotions will subside.

"Think of it like a wave and the peak of the wave is the peak of you wanting to eat. Give yourself 10 minutes and if you still feel like you really want to eat, make an adult agreement with yourself and say, 'Yes, I can have some'. Think about what's going on and what's driving [the impulse] and take the opportunity to think about the longer-term issues too."

I also need to find alternative snacks to biscuits that I can have with my cup of teeth and still satisfy my sweet tooth.

"Going completely cold turkey can make us feel miserable, so try to think of alternatives you can have like a handful of raisins or some fruit.

"It's about being your best advocate, but it's going to be difficult. I'd love to wave a magic wand for everybody, including myself and make it not so difficult, but it's hard denying yourself nice things you're used to having. We're all pre-programmed to like sweet things that are fatty."

Stop Overeating: The 28-day Plan To End Emotional Eating by Dr Jane McCartney is published by Vermilion, priced £10.99.