12 May 2010

Dieting the scientific way

Another day, another attempt to lose weight? Hmm... sounds like it's time to ditch that old diet and try these top new fat-shifting tips instead.


Another day, another attempt to lose weight? Hmm... sounds like it's time to ditch that old diet and try these top new fat-shifting tips instead, says JEROME BURNE of READER'S DIGEST.

Once upon a time, staying a healthy weight was easy. It could be summed up by the phrase "kilojoules in equal kilojoules out". So to lose weight you simply had to practise the reverse of good financial management - spend more than you earned.

Unfortunately for many, but perhaps not surprisingly, it turns out that people are rather more complicated than bank accounts.

A lot of research has gone into unravelling the intricacies of our personal fat accounts - driven by the dream of winning the billiondollar prize of an effective fat pill. Some of the findings have been, to put it mildly, counterintuitive. They also suggest whole new ways of dieting.

To stay a healthy weight, you need a hormone called leptin to work properly. It sends “I’m full” messages from the fat cells up to the brain, where they go, among other places, to the same pleasure centres that respond to sex and drugs such as cocaine. Obese people produce plenty of leptin, but the brain doesn’t seem to respond to it properly.

Pleasure from eating

Last year, researchers at the Oregon Research Institute scanned the brains of overweight people and found their reward circuits were underactive. They were eating more to try to get the enjoyment they were missing. In other words, the study showed that fat people are actually the opposite of greedy - because they get less pleasure from eating than others do.

There’s a lot of evidence for the idea that most, if not all, of us have a set point around which our weight can vary by about 5-10kg, but anything beyond that is a real struggle. This goes for naturally thin people trying to gain weight as well.

Making changes is hard, particularly if your body is working against you, because - as the leptin example shows - the whole weight control system is intimately interconnected with our pleasure centres.

So if your body is sabotaging your efforts to lose weight, why not ditch the traditional approaches and try some new methods based on the latest research, which work with your body rather than against it.

The eat-every-other-day diet

Of course you can still follow the welltrodden route of cutting kilojoules, and by sticking to around 6200 a day you will lose weight. Other upsides are that the kilos should stay off and you could become much healthier: the risk of all the big killers - heart disease, cancer, diabetes - will plummet, along with that of allergies, asthma and infectious diseases. The downside is that you could be constantly hungry and miserable.

But what if you could get all those benefits without being in a permanent state of semi-starvation?

Well, maybe you can. The trick is to try an “alternate day” diet. Several years ago, researchers at the National Institute on Ageing in Baltimore reported that when they gave rats very little food one day and allowed them to eat plenty the next, they showed virtually all the benefits of a permanent kilojoule-restriction diet. The same goes for humans, according to Dr James Johnson, who has set up a website with information on how to do it.

Hormonal changes

How does it work? Besides forcing the body to burn fat, it may also trigger hormonal changes, such as ramping up the activity of two anti-ageing genes called SIRT3 and SIRT4. Most people say that the diet takes a bit of getting used to, but is not as grinding as trying to cut back every day.

Recently published research from the University of Illinois at Chicago of a ten-week trial on obese patients who followed a form of the alternate-day diet revealed weight losses ranging from 4.5 to 12kg, whereas the researchers expected an average of around 2kg.

Blood pressure, heart rate and cholesterol were also lowered.

Men: check your testosterone level

If you’re a middle-aged man whose middle is spreading, it may not just be that you are exercising less and eating more: you could be making too much of the female hormone oestrogen.

Although we talk about male and female hormones, both sexes make both, and we all use testosterone to make oestrogen. This is particularly significant for older men, because as we age, we not only make less testosterone, we also turn more of it into oestrogen.

The extra oestrogen encourages more fat to be laid down around the middle - just the place where fat stores are linked to an increased risk of diabetes and heart disease. This sets up a vicious circle. The newly stored fat pumps out more of the enzyme that turns testosterone into oestrogen.

Break the cycle

To break the cycle, you could exercise to give yourself energy and build muscle - although your reduced testosterone will make that option less appealing. A testosterone supplement, which a few doctors prescribe if levels have become very low, may help.

You could also stop drinking; having to clear away regular large amounts of alcohol means your liver is less
efficient at getting rid of the extra oestrogen.

The sun’s brighter side

Vitamin D is the new nutrient superstar, linked with a lower risk of disorders including heart disease, diabetes, multiple sclerosis and rheumatism.

Now it seems it also helps with weight loss.

During 2008, in a trial of 38, a researcher from the University of Minnesota reported that people with more vitamin D in their blood lost more weight. For every extra nanogram per millilitre (ng/ml) the trial participants lost an extra 200g.

Other trials have linked higher vitamin D levels with less obesity. But why? All experts agree that lots more
research is needed – but in the meantime, one interesting theory is emerging from Imperial College London.

Because sunlight is the main source of vitamin D, a low level of vitamin D may make the body think that winter is on the way, and therefore that it has to store more food.

There’s also debate about how much you should get. The recommended daily amount is 200 IU (international units) but many experts now suggest 1000 or even 2000. A daily dose of 1000 over several months would raise your blood level by 10ng/ml, meaning you could lose 2kg on top of what you’d expect to on your diet.

Keep cool

Older dieters may remember something called brown fat. Unlike the undesirable white stuff, this was a dieter’s dream. Instead of storing excess energy as fat, brown-fat tissue burnt it off to keep you warm - at least in mice.

Brown fat fell out of favour because researchers couldn’t find much of it in humans. But now, thanks to the New England Journal of Medicine, it’s back in fashion.

The idea is to expose people to cold temperatures; they then make more brown fat and their weight drops.
Women in an environment kept at 22C used up 27 more grams of body fat a day than those at 27C. So turn down that thermostat.

Plump and proud

But is being overweight necessarily unhealthy? A groundbreaking 2007 study in The Lancet found that about 30% of people classed as obese (ie, with a body mass index of 30 or more) were in fact metabolically very healthy, with low cholesterol, blood pressure and blood sugar. They were also responsive to insulin - which fatter people aren’t supposed to be.

In short, one in three of those being endlessly cajoled to lose weight may not need to. In fact it may be actively harmful.

Researchers from the University of Montreal compared the effect of a low-kilojoule diet on a group of metabolically healthy obese people with a group who were obese and at risk. They found insulin resistance (a
marker for diabetes) improved by 26% in the at-risk group, but got 13% worse among the metabolically healthy.

So even if your BMI is officially dangerously high, but you eat pretty well, take regular exercise and feel fine, have your metabolic markers checked: if they are healthy, then maybe just enjoy your extra kilos!

(This is an edited version of an article that originally appeared in the May 2010 edition of Reader's Digest magazine. For more information, or to subscribe to the magazine, visit


Read Health24’s Comments Policy

Comment on this story
Comments have been closed for this article.

Live healthier

Exercise benefits for seniors »

Working out in the concrete jungle Even a little exercise may help prevent dementia Here’s an unexpected way to boost your memory: running

Seniors who exercise recover more quickly from injury or illness

When sedentary older adults got into an exercise routine, it curbed their risk of suffering a disabling injury or illness and helped them recover if anything did happen to them.