By
John Naish
PUBLISHED:
18:23 EST, 23 April 2012
|
UPDATED:
19:03 EST, 23 April 2012
Yo-yo nightmares: However hard we may try, research increasingly suggests that diets actually encourage our bodies to make us fatter
Michelle Underwood knows only too well the agony of failed diets. The 36-year-old mother-of-three from Woking, Surrey, has seen her weight yo-yo from 11st to 19st repeatedly over the past decade, as a succession of diets initially worked, then failed spectacularly — leaving her heavier and more desperate than ever.
Michelle blames herself for her serial dieting failures, saying she lacks willpower and has an appetite for the wrong food.
Last week saw a high-profile example of this common problem, when broadcaster Jenni Murray revealed in the Mail how she has piled back on the 5st she lost last year on the controversial Dukan diet.
She had dropped from 19st to 14st,
with the intention of losing another two. But all the hard work came
undone in a matter of five weeks on an extended holiday, she said,
followed by a diet-free Christmas.
Murray has now joined WeightWatchers and believes she has finally found a diet that works for her.
One must admire her optimism and wish her luck. But scientific evidence increasingly points to a far deeper problem that confronts dieters: cutting out calories changes your metabolism and brain, so your body hoards fat and your mind magnifies food cravings into an obsession.
Slimmers have often feared this was somehow true, but now science confirms this cruel fact of nature. New research shows dieting raises levels of hormones that stimulate appetite — and lowers levels of hormones that suppress it.
No-win situation: A new study has shown that dieting raises levels of hormones that stimulate appetite, while causing your brain to magnify food cravings
Meanwhile, brain scans reveal that weight loss makes it harder for us to exercise self-control and resist tempting food. Worse still, the more people diet, the stronger these effects can become, leaving some almost doomed to being overweight as a result of their attempts to become slim.
And as research lays bare the dangers of yo-yoing weight, some experts argue it would be better not to diet at all.
Michelle’s story epitomises these problems. Until she was 25 she weighed around 10st, a normal weight for someone 5ft 8in tall. She stayed slim even after the birth of her two sons — now in their teens — but when she and her partner, Paul, 37, moved in together in 2001, the weight piled on.
‘I have increasingly developed an appetite for the wrong foods,’ she says. ‘I go all day without eating, then Paul comes home late from his job as an NHS estates officer and we get a takeaway. That’s despite having gone to the supermarket to buy food to cook.’
Within a year she weighed 15st, going from a size 12 to a size 18. After the birth of her daughter in September 2003, she weighed 16st. And so began a depressing cycle of diets, weight loss then gain.
No success: A high-profile example of failed diets came to the fore last week when broadcaster Jenni Murray (above) revealed in the Daily Mail how she has piled back on 5st after trying to controversial Dukan diet last year
Over the next nine years she tried a variety of diets, including homespun regimens and hypnotherapy. She lost up to 6st a time, only to regain it within less than a year. ‘Holidays are my downfall,’ she says. ‘Especially package holidays where all the food is included.’
At one point, in 2008, with the help of WeightWatchers and Lighter Life, she lost 6st in less than five months. She was thrilled. ‘When I’m eating healthily, I feel better and sleep better. I also feel more confident,’ she says.
But Michelle’s diet foundered again in 2009 while on holiday. ‘I got fed up feeling weak and light-headed. It affected me psychologically; I felt obsessed with food.’
Michelle now weighs 19st — the heaviest she’s been — and is desperate to lose the weight once and for all. ‘When I’m overweight, I don’t want to go anywhere or meet new people. I won’t even take my daughter swimming, even though she wants to go, and the leisure centre is right by our house.’
COULD NEW WEIGHT-LOSS DRUGS BE THE ANSWER?
There have been various attempts to produce an effective diet pill, only for many to be withdrawn due to dangerous side-effects.
Reductil was pulled from the market in 2010 because it raised the risk of strokes and heart attacks. Then last year Rimonabant, which blocks receptors in the brain that stimulate the appetite, was withdrawn after reports of depression and suicidal thoughts.
The only remaining prescription weight loss pill is Xenical, which prevents fat absorption. But at best you will lose 10lb a year and a known side-effect is faecal incontinence.
But a new range of options is emerging. First among them is Qnexa, which is claimed to help users drop an average of 11kg (24lb) in a year.
The drug is a combination of two old drugs. One is the amphetamine-type weight-loss drug phentermine, licensed in 1959, which suppresses appetite. The other is the anti-seizure drug topiramate. Developed in 1980 to treat epilepsy, it also creates a feeling of fullness.
However, Qnexa has a nasty raft of possible side-effects, including birth defects, addiction and heart problems, making it too dangerous for widespread use.
Close behind Qnexa comes lorcaserin, which targets the brain’s feel-good chemical serotonin to reduce appetite and increase energy.
Another mixes the anti-smoking drug bupropion with a drug called Naxolone, which blocks pleasurable feelings (such as those triggered by sweet and fatty foods).
The difficulty is that nearly all the drugs licensed so far are pharmaceutical blunderbusses: they target brain chemicals such as serotonin and dopamine, which are crucial for other bodily processes.
Despite these risks, most observers think Qnexa will get the go-ahead in the U.S. Perhaps a better alternative is the new wave of diet aids based on diabetes treatments.
These mimic the action of hormones in the gut, and help slow the rate food is digested, making you feel fuller. They are being tested to see if they are a genuine weapon against obesity.
Professor Stephen Bloom a hormone researcher at Imperial College, London, warns: ‘Producing a safe and effective diet drug is a big challenge. Inevitably healthy 15-year-olds are going to get hold of it and we can’t afford to make them ill.’
JEROME BURNE
Michelle’s story is an extreme example of a problem that seasoned dieters know only too well — the heartbreaking curse of the ‘rebound pounds’.
Now a swathe of scientific evidence points to a disheartening fact for the 25 per cent of Britons trying to lose weight at any one time: our basic human biology is the greatest enemy of committed slimmers.
Researchers, including Joseph Proietto, a professor of medicine at the University of Melbourne, have uncovered one of the main possible reasons. Two years ago, his team recruited 50 obese men and women, and coached them through eight weeks of an extreme 500-to-550-calories-a-day diet (a quarter of the normal intake for women).
At the end, the dieters lost an average of 30lb. Proietto’s team then spent a year giving them counselling support to stick to healthy eating habits. But during this time, the dieters regained an average of 11lb. They also reported feeling far hungrier and more preoccupied with food than before losing weight.
As the researchers reported in The New England Journal of Medicine, the volunteers’ hormones were working overtime, making them react as though they were starving and in need of weight-gain. Their levels of an appetite-stimulating hormone, ghrelin, were about 20 per cent higher than at the start of the study. Meanwhile their levels of an appetite suppressing hormone, peptide YY, were unusually low.
Furthermore, levels of leptin, a hormone that suppresses hunger and raises the metabolic rate, also remained lower than expected.
Proietto describes this effect as ‘a co-ordinated defence mechanism with multiple components all directed toward making us put on weight’. In other words, the body had launched a backlash against dieting.
The team’s landmark study reinforces a belief among biologists that the human body has been shaped by millennia of evolution to survive long periods of starvation.
The human frame contains around ten times more fat-storing cells in relation to its body weight than most animals (polar bears, which have to endure long stretches when prey is unavailable, are similarly fat-rich).
Our calorie-hoarding frames have strong mechanisms to stop weight loss, but weak systems for preventing weight gain. If you manage to lose ten per cent of your weight, your body thinks there’s an emergency. So it burns less fuel by slowing your metabolism.
The body learns to function on fewer calories, resetting your metabolism. The problem is if you then stop dieting and start eating more again, those extra calories are stored as fat.
This effect kicks in after around eight weeks of dieting — and can last for years. Studies by Columbia University show this metabolic slowdown can mean that just to maintain a stable weight, people must eat around 400 fewer calories a day post-diet than before dieting.
Why would this be so? Muscle samples taken before and after weight loss show that once a person drops weight, the fibres may change to become more fuel-efficient — burning up to a quarter fewer calories during exercise than those of a person at the same weight naturally.
How long this state lasts isn’t known, though some research suggests it might be up to six years.
It’s also thought the brain changes in the way it reacts to food. This wilts our willpower, according to Michael Rosenbaum, a researcher at Columbia University Medical Centre who studies the body’s response to weight loss.
‘After you’ve lost weight, there’s an increase in the emotional response to food,’ he says, adding that there is also ‘a decrease in the activity of brain systems that might be more involved in restraint’.
Nature lets us down: Our calorie-hoarding frames have strong mechanisms to stop weight loss, but weak systems for preventing weight gain
In 2010, Rosenbaum and his colleague, Joy Hirsch, a neuroscientist at Columbia University Medical Centre, scanned the brains of people before and after weight loss while they looked at objects such as grapes, chocolate, broccoli and mobile phones.
After losing weight, the scans showed a greater response in the areas associated with reward and a lower response in those associated with self-control.
And last year, scientists at the Albert Einstein College of Medicine in New York discovered that when starved of food, brain cells actually consume each other. This causes the release of fats, which in turn results in higher levels of a powerful brain chemical that stimulates appetite, the journal Cell Metabolism reports. All bad news for dieters, as going without food could make them even hungrier.
All of this helps to explain why an analysis of 31 long-term clinical studies found that diets don’t work in the long run. Within five years about two-thirds of dieters put back the weight — and more. The researchers from the University of California found that dieting works in the short term, with slimmers losing up to 10 per cent of their weight on any number of diets in the first six months of any regimen. But after this, the weight returns, and often more is added, says their report in the journal American Psychologist.
The analysis concluded that most volunteers would have been better off not dieting. Their weight would be pretty much the same and their bodies would not have wear and tear from yo-yoing.
This backfire effect is worst among teenagers: people who start habitually dieting young tend to be significantly heavier after five years than teens who never dieted. This mix of biology and psychology translates into a sobering reality: once we become overweight, most of us will probably remain that way.
Certainly, we should all be worried about what dieting does to our health. Restricting calories may increase the risk of heart disease, diabetes and cancer, according to a study from 2010 in the journal Psychosomatic Medicine.
Ultimately, of course, we should be more wary of piling on the pounds, than relying on diets to reverse the damage. As Tam Fry, chairman of the National Obesity Forum, says: ‘The way that the body protects itself against weight-loss diets is quite incredible. Putting on weight is for most people, sadly, a one-way street.’
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People gaining weight eat too many calories – of course they will have to eat less calories than before if they want to maintain weight loss. It’s not about denying yourself tasty foods for a couple of months and then returning to your old habits, that doesn’t make any sense. Eat what you like in small portions, calorie count exercise. 4 and a half stone, 5 years and counting – it’s not impossible!
- Kirsty, Dubai, 24/4/2012 06:27
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I live by this mantra, I have always maintained that exercise is the key to weight loss and habit forming so you stick with it. It doesn’t have to be thrashing it in the gym for hours on end, you could skip your soaps/reality tv programmes and take the kids out for a walk or play with them, leave the kids with the husband/wife and alternate turns to go out for a swim/class each night or the couch to 5k is a fantastic programme to start running and it doesn’t take long. I personally eat good food anyway. I do not buy ready meals and cook all of my own food, it’s not rocket science and thankfully my mother always cooked meals herself, cooking healthy meals for my family. I simply do not have cakes, chocolate, biscuits, pop, crisps or anything of the like in my house as my mother didn’t so if it’s not there its not an option and I don’t have it.
- cfj5, No of ewe business boyo, 24/4/2012 06:24
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You do not need to starve yourself or do without to lose weight. I have been going to slimming world since Jan and have lost well over 2 stone. Swapping processed and convenience foods for made from scratch recipes are the key, and they do not take long to make. Home-made curries, chilli, bolognese and soups, instead of processed jars which contain high sugar levels. I am not on a diet, I have changed my lifestyle
- Sandra, Southport, 24/4/2012 06:06
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Rubenene, it isn’t rubbish. People who lose weight through dieting only keep it off if they continue to diet (e.g. continue to undereat). As soon as they start to eat normally (which doens’t mean overeating or eating junk), they’ll put the weight back on in a heartbeat. This happens to all dieters, they’ll all tell you. If they keep the weight off, it is only because they’ve continued to diet.
- Superfry, London, 24/4/2012 03:41
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Years ago we didn’t know that smoking caused most lung cancers. Those who found it difficult to give up were given sympathy. Those who are now obese and have had fluctuating weights for years have my sympathy. Now that we have this information though, anyone who chooses to become overweight in the first place obviously isn’t suffering from it. Just like cigarettes, don’t put yourself there in the first place. In hunter gatherer societies people’s weight fluctuated according to however plentiful food was. Lots of food, lots of fat, no food, lost the fat. You know there’s not going to be a famine, so you don’t need to stock up.
- winnie, Melbourne, Australia, 24/4/2012 03:12
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This is absolute RUBBISH. If you lose weight gradually and healthily and thereafter keep a check on your eating and exercise patterns, there’s no reason in the world you need to re-gain your lost weight. People who are trying to lose weight, don’t be discouraged by these articles – they’re not true!
- Reubenene, Somewhere In The World, 24/4/2012 02:54
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The only thing that works is a lifestyle change, as opposed to dieting. Keeping an eye on what you eat, the quality of your nutrition and making sure to get enough exercise, as the body is not designed to be inactive. I also agree with the set weight hypothesis. When I try to go below a certain weight, that is within the normal range for my height, I start craving food like crazy and binge eating and this appears to happen to a lot of people. It is best to eat intuitively, as your body will let you know what it needs and when it needs it, generally.
- Kate, Southampton, Uk , 24/4/2012 02:19
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This article is all basically correct, but fails to mention the “set weight” hypothesis. People who don’t diet don’t obsessively monitor every calorie that goes into their mouths, and on the whole eat more than 2000 calories a day. Yet, their weight remains stable. Why? Because your body has a set, preferred weight that it works hard to maintain, so if you eat a few too many calories, they are simply burned off as heat, and if you eat a few too few, your body makes you hungry to make up the deficit. Weight gain only occurs in people who significantly and consistently overeat far past hunger signals. The problem is (for women at least) that their “set weight”, although healthy, is usually higher than they would like it to be, which makes them start dieting – thus the trap is set. And the very lucrative dieting industry knows this only too well.
- Superfry, London, 24/4/2012 01:59
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Simple answer. Focus on a healthy lifestyle and ditch the word diet from the english dictionary.
- Stacey, UK, 24/4/2012 01:49
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WOW !! This is news – anyone following such ludicrous diets as Dukans will have to follow them for their entire lives to maintain the initial weight loss !! THEY DON’T WORK FOOLS !!!
- david, chelseaville, 24/4/2012 01:28
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