Want to shift some pounds this January? You could scrupulously avoid sugar, starches, beer and butter. Leave off champagne, puddings and pastries. Or you could run every morning, followed by a good scrub down and a meal of something filling but fat-free. Because as night follows day, so the season of festive feasting must be followed by a diet or detox to get rid of the paunches and fleshbelts we had so much fun putting on.
But the regimes above aren't cribbed from the pages of the latest diet tome and are not the gospel according to Madonna's new personal trainer. They're taken from, respectively, a pamphlet published in 1863 by William Banting, as shining a star in the world of dieting then as Dr Robert Atkins was in the 20th century, and the writings of the Greek physician Galen, a follower of Hippocrates, who was helping people achieve bikini bodies in 2BC – 2,000 years before the bikini was invented.
We've been trying, collectively, to lose weight for more than two millennia, as medical historian Louise Foxcroft explains in her new book, Calories and Corsets: A History of Dieting over 2,000 Years. Foxcroft fixed on the topic of weight-loss schemes after speaking to a friend who's a medic. "She said that whenever she gives talks, as soon as she mentions diet drugs, everybody in the audience perks up. I thought that was so interesting, so I decided to see if I could use the history of dieting to throw light on the assumptions we make about our health."
And what Foxcroft found was 20 sorry centuries of bingeing, purging, snake oil and strange ideas about what we look like and why. While the Greeks had a sensible approach to fat-fighting ("the Greek word diatia, from which our word "diet" derives, described a whole way of life... an all-round mental and physical way to health"), the early Christians were rather more conflicted about excess flesh. As Foxcroft explains, "the heroic abstinence and starved bodies of early ascetics such as the third-century Saint Anthony were often the subject of exaggerated glorification". No doubt their constant prayer ran something along the lines of "nothing tastes as good as God feels".
One of the first regimes to tackle weight loss for its own sake (to achieve an "ideal body" free from "undue thinness and fatness") was an 11th-century plan created by Avicenna, a Persian physician and philosopher, who advised the fat to eat only bulky food with little nutrition in it, and to get it out of the body as quickly as possible using exercise and laxatives. As Calories and Corsets makes clear, when it comes to dieting, plus ça change, plus c'est la même chose. Equally, the first modern "bestseller" was a 15th-century work, De honesta voluptate et valetudine by Bartolomeo Sacchi (Il Platina), which brought collected recipes to bring pleasure (voluptate) and health (valetudine) to its readers. Diet books have been money-spinners ever since.
But according to Foxcroft, people really got a taste for dieting during the 19th century. "People dieted mainly for health reasons and then in the mid-19th century it tips over into dieting more for aesthetic reasons. It's to do with people moving into urban environments, having access to different and more refined foods and the explosion of the media," she says. Ideas about body shape also underwent big changes from, she says. "Corsetry has been going for hundreds of years but in the Victorian age the corsets and the bustles really defined the sexes quite spectacularly." A generation later, there was a backlash against this womanly silhouette and a move towards more boyish figures. "After the First World War there just weren't any boys about and the girls begin to look like boys, with breast binding and dresses that fall from the hip."
The reasons for this physical metamorphosis and the fad diets – books such as Why Be Fat? and cigarette advertising that reinforced the message that smoking made women slim – that came in its wake are surprising. "Body shape and what we see as the ideal is far more linked to economics and whether we're in a time of war and peace than we might imagine," Foxcroft says. "During the First and Second World Wars, if you were overweight it counted against you because it looked as though you were taking more of the rations than you should have done. Then in times of austerity, and I suppose arguably that's having an effect now, there's a great deal being said about obesity. It's like a pendulum."
But Foxcroft is unconvinced by the quick-fix promises of many a diet regime. "Fad diets are little better than useless. They do the biggest business and arguably the greatest harm. Dieters can lose 5 to 10 per cent of their weight, but the weight almost always comes back." So why do we keep on trying? "The process is like falling in love," she says. "It provokes the same feelings. You are yearning for something. Food is the immediate desire and thinness the more remote but possibly achievable goal. You dwell obsessively on the object of your love." She advocates the unglamorous approach of eating less and moving more, focusing on healthy foods, fewer carbs and the odd biscuit.
So what does the future bring? Meals in the form of pills? Diet drugs for breakfast, lunch and supper? "I think there'll be a backlash against plastic surgery and diet drugs. From the first 'apronectomy' in the 1890s, it's become a norm, but the pendulum will swing back again, and I think it has to."
Other than learning about the things humans will do to be slim – taking digitalis, eating just the yolk of the egg as your entire daily repast – what has Foxcroft taken away from her time studying the history of diets? "I did think that actually I would be a lot better off if I wrote a diet book! I know how to do it now. You just need certain phases, a good back story, a celebrity to endorse it and bingo! Set up a website and off you go." However, she has used her forces for good and laid bare the barminess of fad diets. She does wish one thing, though. "That we could make the idea of moderation sexy. You really don't have to go from one extreme to the other."
Could next year's health bestseller be The Moderation Plan? I'd like to think so, but the past 2,000 years show that it doesn't look likely.
Calories and Corsets (£14.99, Profile Books) is published on Thursday