Challenging the empty promises of a multi-million pound industry, this research concludes that diets don’t help you lose weight – in fact, within five years two thirds of dieters put more weight on than they had lost. Crash diets don’t work – it’s that simple.

The no diet-diet

Biologists have long held that when we deny ourselves for any period of time, our bodies react by clinging on to fat cells when we revert to our previous diet, thus making us put on weight – so the size-smaller jeans you triumphantly bought on reaching your goal weight are swiftly consigned to the back of the wardrobe again. last October, a study of a group of 50 overweight women and men by Dr Joseph Proietto at the University of melbourne showed that after dieting our hormone levels start to work overtime, reacting as though our bodies are starving. Put on a very low-calorie diet for 10 weeks, participants lost at least 10% of their body weight. they then resumed a weight maintenance diet – after a year, they had regained an average of almost half the weight they had shed.

The same study found that their levels of ghrelin, a hormone that stimulates appetite, had shot up to 20% higher than at the beginning of the research. On the other hand, their levels of the hormone which suppresses appetite, peptide yy, were low. In addition, they had lower levels of leptin, a hormone that suppresses hunger and raises the metabolic rate. These levels only partially returned to normal within a year. In other words, even if the dieters were ‘good’, their bodies were making it harder for them to stop regaining weight by making them hungrier.

The research subjects had pushed their bodies into crisis mode and triggered an emergency physical response to a lack of food. Charles Burant, director of the University of Michigan nutrition Obesity Research Center, describes our bodies’ automatic response to these deprivations as having been “developed over eons of evolution”. Our ancestors didn’t outlive the dinosaurs by starving themselves, and our bodies have yet to adapt to the fact we want to.

It wasn’t just the physical reaction that worked against the dieters in Proietto’s study. there were psychological effects too. When they went back to normal eating, the participants felt hungrier and more preoccupied with food than before.

“Diets can be rigid and socially isolating… healthy eating isn’t about banning foods”


Keeping up the willpower to permanently combat our enhanced urges to consume after denial – that is, stopping yourself reaching for the cake the minute you come off the restrictive regime – often proves to be a fight that we simply cannot win. research by Dr Michael Rosenbaum of Columbia University medical center proves this, showing that after his subjects had lost 10% of their body weight, there was “a decrease in the activity of brain systems that might be more involved in restraint.” this led to what he called “an increase in the emotional response to food” – after losing weight, food takes on an extra significance – so that Waitrose basket is bound to be full of ‘naughty’ foods once more.

With these physical and psychological factors working against us, it’s not surprising the majority of dieters are unable to keep weight off – as proven in an examination of 31 diet studies by UCLA researchers. “you can initially lose five to 10% of your weight on any number of diets, but then the weight comes back, plus more,” says traci mann, lead author of the study. “Sustained weight loss was found only in the minority of participants, while complete weight regain was found in the majority.” Hardly has you slurping cabbage soup, does it?

The Quick-Fix Myth

A recent survey of British men and women found that more than three quarters had started a diet in the past year – whether it’s the Dukan, the Atkins or whichever other quick-fix we are convinced will turn us into supermodels in a matter of weeks – and the average 45-year-old woman had been on 61 diets in her lifetime. Enter the archetypal female yo-yo dieter.

Louise Foxcroft, a medical historian and author of Calories & Corsets – A History Of Dieting Over 2000 years, says the quick-fix trend began in the 19th century, when the emergence of unhealthy, refined foods coincided with an explosion in media and advertising. “It happened partly because the changing food environment was ruining people’s size and shape, and partly because of the media emphasis on size and shape,” says Foxcroft. Diet drugs were all the rage, an unregulated and heavily promoted easy way out. It’s this promise of a rapid solution that still has us buying into today’s fads. “Attaining a certain body weight and level of health takes time – so it’s enticing to be told it’s easy.”

This echoed 18th-century feminist Mary Wollstonecraft. In her 1792 text A Vindication Of The rights Of Woman she bemoaned the pressures on women to look good, and what they had to go through “to preserve personal beauty”, adding that “artificial notions of beauty, and false descriptions of sensibility have been early entangled with her motives of action”. Foxcroft believes that we haven’t moved on as much as we might think since then.

“We still seem stuck with that traditional idea of viewing women aesthetically, rather than on ability,” she says. It’s not surprising that, under this sort of pressure, we sign up to the latest fad diet.


The origin of the word ‘diet’ is the greek ‘diaita’, but our modern concept of the term is far removed from its ancient root, which was about physical and mental health and how what we eat can enhance our all-round wellbeing. The idea was to eat regularly, moderately and simply, to exercise and to sleep. now, diets are sold to us as magic weight loss wands – South Beach, Blood group, the list goes on. The fact that many of them come with a list of adverse health effects – from halitosis to kidney problems – shows how far removed we now are from the Greek ideal. Sian Porter, nutritionist and spokesperson for the British Dietetic Association, says that these fashionable diets are often nutritionally worthless.

“You’re often missing out on key nutrients,” she says. “Healthy eating isn’t about banning foods, it’s about how often you eat them and the quantities you eat them in. Some of the diets, like Dukan, are also very rigid and socially isolating. With others, like the Blood group Diet, there’s just no evidence base for them.”

A Tasteful Approach

With almost a quarter of people in Britain classed as obese, it’s clear that we do need to improve our eating habits – but how? Diet clubs such as WeightWatchers and Slimming World come under less criticism from medical experts, as they advocate group support and a change of lifestyle. But the key is to understand that the process must be gradual and to stick with it. “Extremes of weight gain and weight loss potentially put strain on the heart and will affect mental health,” says cardiologist Dr Aseem Malhotra, who wants to get away from the modern concept of ‘dieting’.

“I personally would avoid the label ‘diet’,” he says. “It’s about changing our food for life.” His formula is straightforward: “Avoid processed and sugary foods, and eat natural instead. Beware of foods that are marketed as low-fat but which are full of carbohydrates and sugar – if you’re consuming excess amounts of sugar, most of it goes to the liver and gets converted to fat. Avoid snacking and stick to three meals a day, though there’s nothing wrong with the occasional treat. Regular physical activity is a good thing, but that doesn’t mean you can eat as much junk as you like – most people just don’t have the time to be able to burn it all off,” he says.

This is nothing we don’t know already. So perhaps with the weight of scientific research against modern diets increasing, it is time to return to the original concept of ‘diaita’ – a balanced way of eating and living centered around health and wellbeing. No complex regimes. No celebrity endorsements. Just common sense.