It's easy to leave drugs behind. Just start a new life, away from temptation. But where do you turn when you're addicted to food? It's everywhere. William Leith tells Louise East how he beat his eating habit - and more than a few others.
Two hours into my interview with William Leith, during which he has talked almost non-stop and consumed half a glass of mineral water, he pauses and says: "Can I order a beer?" It's a reasonable request, and I'm about to agree when Leith jumps in, saying: "I'm just going to have one. Don't worry. I'll be fine." His riff of edgy laughter would herald mayhem if this were a low-budget thriller. I don't think my face registered anxiety. It had simply not crossed my mind that Leith would veer off on a bender at 5.30pm while promoting his new book. So I can only assume that he is accustomed to seeing people blench when he suggests a quick pint.
Leith's book, The Hungry Years, is subtitled Confessions of a Food Addict, but he is open about being a just-about-everything addict. He routinely took up to 10 painkillers a day - his leaving-the-house routine was keys, phone, wallet, Nurofen - he hoovered up cocaine, drank until he passed out and conducted a series of spectacularly unsuccessful relationships. But, most of all, he ate. Doughnuts, chips, three plates of mash and gravy, burgers, pies, buttered toast. Sometimes he would also exercise for hours at a time, thereby cancelling out some of the effects of all the food, but mostly he just ate.
This went on for years, with Leith remaining just on the functional side of chaos, able to turn in hefty newspaper features on everything from Palestine to Colin Firth but also capable of staying up for days at a time, crashing on strangers' sofas and sleeping in his clothes. Ten years ago he combined the two, Dr Jekyll and Mr Hyde, in a weekly confessional column detailing with compelling virtuosity his adventures in the seedier realms of excess. Colleagues at the Observer newspaper remember him limping into work, trailing blood-stained bandages and wearing food-encrusted jackets, a man so accustomed to being on the edge of a nervous breakdown that he no longer bothered to balance.
But in January of 2003 Leith was sent to New York to interview the late Dr Robert Atkins, creator of the famed diet. It was, he says, the fattest day of his life. At just over 180cm (6ft) he weighed 105kg (16½ stone). As it turned out, it was also the start of two years of dieting, therapy and research that resulted in The Hungry Years. More importantly, it resulted in the Leith I meet in a member's club in Soho: well upholstered but no longer fat; calm, measured and humorous.
In contrast to the staccato brilliance of his writing, Leith in person is loquacious, frequently pausing to ask: "Am I just babbling now, do you think? Am I ranting?" Four months ago he and his wife, Dodie, had their first son, Billy, and Leith has spent the morning pulling up carpets in their new home in Sussex.
So what exactly happened on that fateful trip to New York? "There's a point when you come to the end of your tether. You realise you've been fat for one day too long. Your eating doesn't satisfy you, and being unsatisfied is horrible. You think, Am I going to keep getting fatter and fatter?"
The Atkins diet works on the principle that carbohydrates make your body produce insulin, which breaks down carbohydrates but can also make you hungry again. In other words, the very thing you eat to stave off hunger is making you hungry in the first place. No wonder meeting Dr Atkins was a Damascene moment. "I had always had a terrible physical need to eat carbohydrates. I'd wake up and feel a huge hunger for toast, but then I'd eat five slices and it wouldn't fill me up."
Leith went on the Atkins diet, lost weight and felt better. He no longer drank. He ended an unsatisfactory relationship. But - and this is where the story gets interesting - just when he was at his thinnest he went on a drinking binge. He made an appointment with his coke dealer for the first time in years. Finally, in a scene that even he acknowledges as almost boringly inevitable, he woke up with his head in a pile of someone else's CDs, coated in a thick layer of his own vomit. "At that point I had a second level of awareness, which was, Oh, right, I've sorted out my weight, but there must be more to it than that."
After going through therapy Leith worked out that taking in scary amounts of food, drink or drugs ensured there was no room for scary emotions.
As a child he was shuttled between boarding schools while his father, a brilliant child psychologist, and his mother, an author of books on child-based learning, moved from Britain to Canada to Germany.
Leith was always out of place and picked on, a fat, angry little boy. At the age of seven he crept into his grandmother's pantry and ate first one slice, then two, then the entirety of an apple pie.
"For most people a problem with drink starts at 15 or 16 at the earliest, but food is the first thing you have access to. I remember, during one of my very bad cocaine phases in the mid-1990s, I decided to have a break of four months, and I didn't find it that hard. I could avoid the people I used to do coke with, avoid the places I went to. But, of course, food's always there. We need to eat every day, so food is inevitably going to be really difficult if you've got a problem with it."
There's nothing startlingly new in the idea of poor self-esteem leading to binge eating, of course, nor in the idea of writing about it, but where The Hungry Years differs from most food confessionals is that Leith is a man with what has traditionally been seen as a woman's problem.
"There has been a particularly pernicious relationship between women and body image, which I think is getting worse as time goes by. Women are being made to feel more and more insecure about how they look . But if you look at how the marketplace works, it's only logical that this will start affecting men as well. The industry which preys on women, selling them make-up and skin care and plastic surgery, is approaching saturation point, but it still has to take more market, and the only available space is men. Look at all this very ad-friendly media about men and their bodies. If you can make men feel insecure you can make them buy all these lotions and potions; you can make them have plastic surgery. It's all on the increase."
Leith is interesting on society. For him, an addiction to carbs, cocaine or painkillers is emblematic of the way 21st-century society is driven by consumption. "If you think about it, in a world of consumption and abundance, the only way to ensure you will always have a market is to create more need. So you build the need to consume into the product itself." Like carbs. Like cocaine.
For Leith, the fact that his own excessive consumption was driven by personal unease as much as societal pressure does not contradict his theory but proves it. "I suffered from a terrible neediness which set in at a very young age, but I think that our society is such that nowadays many, many more people feel that neediness."
The indirect causes of that neediness - Leith's parents - have yet to read the book, but he says he's not too worried. "My mother is uncomfortable about the idea that I was unhappy, but we've had the same discussion over and over. Her attitude is always, 'Oh, not this again; you always talk about this.' I always feel that I can't muster the ability to explain. At least with the book I've put it a bit better than I did as a boy."
He acknowledges the irony in his rather pro-Atkins book being published in the month that Atkins Nutritionals declared bankruptcy, but he points out that the principles of the Atkins diet - that fat is not necessarily bad for you and that eating excessive carbohydrates can cause weight gain - have now been widely accepted and are included in new and popular regimes such as the GI diet.
"Part of the reason Atkins went down is that there's now many more versions of that diet, but it's also really hard to make and sell low-carb snacks. Making something fat-free is relatively easy, but extracting the carbohydrate is expensive, and they tend to be poor replacements.
"The low-fat mantra, which lasted from 1970 to 2000, fitted very well with selling products. It was also the period in which we as a society got fatter. There are lots of reasons for that, but one of them is that eating things low in fat often means eating a lot of carbohydrates, and carbs make you hungry," he says.
Leith no longer sticks rigidly to the Atkins diet. After a period in which he forswore bread and potatoes with the vigour he previously used to pursue plates of mash and gravy, he has settled into a life of moderation in all things, including moderation. "I'm not too bad. I'm fatter than I was when I was doing Atkins all the time. I eat some carbs, but I'm careful. There's a memory of bingeing there. I can sip this beer now, but I can still see a shadow self that would have just knocked it back.
"I'm coming to a point where, without being on a diet, I'll leave things on my plate, thinking, well, I'd love to finish it, but I know it will make me feel overfull. I haven't had that feeling for a long time, and I think that's the beginning of things working out. That's the beginning of things being really good."
The Hungry Years: Confessions of a Food Addict is published by Bloomsbury, £10.99