For Jyoti Jackson, teaching was more fattening than chocolate, cake and crisps combined. And as the workload piled on, so did the pounds. Before she knew it, she was a size 22.
"I absolutely love teaching, but it's hard to maintain a work-life balance," says Mrs Jackson, who is head of ICT at The Latimer Arts College in Kettering, Northamptonshire. "I didn't have time to eat, so I'd just grab something from the canteen when I could."
That invariably involved something with cheese: A cheese sandwich, cheesy chips or a potato with cheese. For a vegetarian, there wasn't much choice available, but Mrs Jackson needed that calorie hit.
"I'd mark three pieces of work and then reward myself with a coffee and a biscuit from the staffroom," she adds. "I eat when I'm stressed, and sometimes school can be a very busy, stressful environment."
She is not alone. Research consistently reveals that employees respond to high levels of stress by making unhealthy lifestyle choices, such as turning to drink, drugs or overeating. Interestingly, teachers are more likely than other professionals to shun the drink and drugs, and turn to food as a coping mechanism instead.
Teachers are the third most stressed workers in Britain, according to a survey by the Stroke Association last year, second only to recruitment and the law. Almost half respond to the pressures of the classroom by binge eating.
This may have something to do with the high proportion of women in education - generally speaking, comfort eating is more common among women than men.
Recent research from Weight Watchers found that almost two-thirds of women admit that "emotional eating" - eating regardless of appetite or hunger - contributes to their weight gain. Men do sometimes eat in response to emotional cues, but they tend to be positive, it adds. Women eat if they are sad, bored, angry or stressed.
Liz knows all about that. "Teaching makes me fat," says the secondary school teacher from Hull. "I know all the things I should do to take care of myself, but teaching makes me stressed and when I'm stressed all self- care goes out of the window. I don't cook properly, I don't exercise enough and I just want to eat all the time."
Dr Jacquie Lavin, a nutritionist with Slimming World, says some women comfort eat in order to forget, while others eat to remember. "They'll often crave childhood food that their mother used to cook them," she says. "It takes them back to happier times, which they need when they're not feeling so great."
For Mrs Jackson, food was always a big part of her Asian family life. She was overweight as a child but put on much more during and after her two pregnancies. Then came teaching.
"I didn't have time for breakfast, would be too busy to sit down during break and had clubs every other lunchtime," Mrs Jackson says. "Then it's back to the kids, followed by planning and preparation or marking. I simply didn't think I had the time to eat healthily."
This is a common misconception, says Emma Donaldson-Fielder, a chartered occupational psychologist with the Affinity Health at Work group. "People are always in a hurry nowadays and they feel healthy eating takes longer," she says. "But it can be built into your lifestyle and can actually save you time."
Cycling into work can be quicker than getting the bus, she says, and it can take just as long to order a take-away as it does to cook a light, healthy meal. Simply choosing a potato salad at the canteen instead of a burger and chips can help.
Somehow though, healthy food doesn't always seem to hit the mark, especially during long, demanding days in the classroom. There are biological, as well as psychological, reasons for this. Carbohydrates or sugary foods can boost your mood and provide a short-term energy boost, says Ms Donaldson-Fielder.
This is followed by a blood sugar "crash", lower serotonin levels (which can prompt depression) and the need for a further sugar hit. If it is not burnt as energy, the sugar will be stored in the body as fat.
This downward cycle can be notoriously hard to break, especially with the consistent levels of stress that teachers experience. A heavy workload, lack of support or a diminishing sense of control (through lack of consultation with the senior management team), can lead anyone to make poor dietary choices, says Ms Donaldson-Fielder, as can badly managed change, staffroom bullying or poor management.
"Employers and employees need to take joint responsibility to minimise stress that may lead people to make unhealthy choices," she believes. "Just providing a good supply of drinking water can help. Weight gain is massively multi-factorial though. What makes one person overeat will make the next person not eat at all."
Donna, a reception teacher in the Midlands, loses weight during term time and gains it during the holidays. "I have put on a good 8lbs during the summer holidays and feel healthy and energised," she says. "It is when I lose all that weight while at school that I feel and look unhealthy."
The opposite is true for Linda Buchanan, a teacher at Biggin Hill Primary School in Kent. She has always had a weight problem, but peaked at 16 stone two years ago - well above the UK's average female weight of 10 stone 3.5lbs. With the help of Slimming World, she has dropped five and a half stone.
"Before, I didn't plan what I was going to eat, I just had what was there," says Ms Buchanan. "Instead of lunch, I'd have a chocolate biscuit from the staffroom and snack on a bag of sweets I'd brought in."
She did not have time to feel hungry until the end of the day, when she'd be back at home with her husband and three children. Now, she builds healthy food into her day - even if it means visiting the supermarket at 6.30am on a Saturday.
"I make sure I'm never caught short with food," she says. "I either take in a packed lunch or fall back on a stash of healthy food in my classroom cupboard," she says. "I'm surprised it hasn't been harder to lose the weight."
Joanne Juliff, head of history at Morriston Comprehensive School in Swansea, could control her eating in school but not at home. "There are only set times of the day when you can eat in school, but my real problem was the early 3pm finish," says Ms Juliff.
"It left me with very long evenings. My automatic response was to come home and have toast - the dieter's enemy - crisps, tea or biscuits. I wasn't really hungry, but it was a habit, especially in winter when it's cold and dark."
When stressed, Ms Juliff would also have a couple of glasses of red wine as a relaxant. "I know that's very common among teachers," she says. "You get into the habit of wanting it, but alcohol is just empty calories, and then you get peckish and want some crisps to go with it or something."
The pounds crept on. Ms Juliff has struggled with her weight since she was a teenager but a couple of years ago she hit 15 stone 13lbs and was wearing size 20 clothes. She is now four months pregnant with her third child, but is still a size 12, having lost five stone in less than three years.
Weight Watchers has helped her, she says, but the school has not. "The canteen hasn't improved much in my opinion," she says. "They have a `no chip day', but they'll still have pizza or fatty sausage rolls throughout the week. I don't want to risk it - I'd rather take in leftovers from my tea the night before."
The Healthy Schools programme, now in its 10th year and in almost all English schools, aims to get pupils exercising more and eating less junk. The shift in mindset is crucial if rising childhood obesity figures are to be stemmed. To date, there are almost 2 million overweight schoolchildren in the UK, of which about 700,000 are obese, the International Obesity Taskforce says. But in the bid to get young people up and running, are their teachers - who should be good role models - being forgotten?
Phoebe Rowell, from Healthy Schools, is adamant that the programme benefits the whole school community. "The more schools take part in Healthy Schools, the more it rubs off on everyone else, teachers included."
At Rift House Primary School in Hartlepool, teachers are aware of the need to be good role models, says Carole Carroll, headteacher. In response to some of the Healthy School changes, teachers are choosing water instead of coffee, joining local gyms and buying healthy food from the pupils' fruit tuck shop.
"The biggest stress for teachers was the poor behaviour," says Ms Carroll. "They were working their socks off but standards were dropping, which was demoralising." She claims that the shift to a more active, theme-based curriculum has changed all that and the feel-good factor has risen respectively, leading to teachers making healthier choices.
At Bydales Technology College in Redcar, teachers have begun cycling to work, taking more exercise and participate in the college's weekly football match. Others have taken part in a local fun run and have joined a healthy cookery club. The benefits extend beyond staff's physical and emotional wellbeing, says Tony Hobbs, headteacher. "It's also increased teachers' motivation and sense of team spirit throughout the school."
ut other teachers report that the pressures of the job are hindering their ability to stay fit or eat sensibly. The stress affected Lisa to such an extent that she gave up her full-time post and went into supply teaching.
"The constant self-evaluation and criticism of teaching impacted upon my already chronically low self-esteem," she says. "Stress and depression pushed me right back into my cycle of comfort eating."
Planning at her computer only seemed manageable if she had a packet of Mamp;Ms at her side, and she was too tired to exercise. "If I'm off work I'll quite often forget to eat over the course of the day, but if there's the lunch break, my stomach is counting down to it. Then you roll in from work, tired and hungry, and there's the take-away menu, nice and accessible.
"One reason I dropped out of full-time teaching was to get my work-life balance sorted, improve my mental wellbeing and shift the weight."
Other teachers feel the same. Angela is convinced that work-related stress, frustration and anger contribute to her overeating. "I also find it hard to commit to exercise during term, as I'm so busy and shattered."
Yet exercise and healthy eating is more important than ever during periods of lethargy and stress, says nutritionist Dr Jacquie Lavin. "People forget to look after themselves during difficult times, but they absolutely must," she says. "It will help them feel more confident and in control of at least one thing in their life."
Most will find exercise energising, not tiring, she adds. It can also help clear the mind and act as an effective anti-depressant.
Dr Lavin is increasingly encountering men who are extremely self-conscious about their weight, plus "apple shaped" women who carry fat on their midriff - usually a sign of too much alcohol.
"Unhealthy food and drink is so accessible now," she says. "Junk food is available 247 from newsagents, vending machines, fast food restaurants and petrol stations. Even as you queue up at the supermarket, there's temptation right in front of you."
However, resistance is not futile. A lot is down to forward planning: shopping for the week ahead; cooking double, freezing the leftovers and taking it into school the next day; having healthy snacks in the classroom, or getting up half an hour earlier to do an exercise DVD while the kids are asleep.
But even that may be too difficult for some teachers, who are run ragged by the demands of the job, be it marking, planning or doing paperwork.
"I work a 60-hour week, eat too many biscuits in the staffroom and then go out to dinner and eat comfort food and dessert because I think, `stuff it, I deserve it, I've worked hard'," says one secondary school teacher from Manchester. During the holidays, she lost half a stone through a better diet and exercise, but predicts that will all go back on during the autumn term.
Mrs Jackson, however, has managed to keep the weight off. It started with wanting to get into a black dress for last year's Christmas party. Within a month, she lost a stone; within 8 months, she'd lost 3.5 stone. She is now a size 1214.
"I make sure I pack a healthy lunch and have bowls of fruit in the classroom," she says. "I have a box of Ryvita in my drawer and jellies in the fridge. The whole school knew about my target and even parents would stop me in the street and ask me how I was doing. On the last day of last term, July 16, I reached my target weight."
Lots of teachers at Latimer College now do Slimming World. They are mutually supportive, share recipes and take it in turns to bring in healthy lunches. This sense of togetherness is key to success, believes Mrs Jackson. "This term I want to get everyone out of their department staffrooms and make sure we eat together at least once a week. It allows teachers to mix, share issues and take some time out during the day."
Schools and teachers need to take similar steps if they are to eradicate the barriers to a healthy lifestyle. Those that do may inspire their pupils to follow suit - saving them from a lifetime of health-related problems. For what good is an education, if we don't also teach pupils how to minimise the risks of developing cancer, cardiovascular disease or type 2 diabetes?
www.weightwatchers.co.uk; www.slimmingworld.com; www.healthyschools.gov.uk
Teach yourself weight loss