By Kate Kelland
LONDON, Dec 7 (Reuters) – Forget fad diets pushing cabbage soup, weight-loss shakes or maple syrup. Swapping fatty foods for low-fat alternatives will keep you slim – and now there’s World Health Organisation-backed research to prove it.
A review of 33 trials involving 73,589 men, women and children in America, Europe and New Zealand found that choosing low fat foods helped people lose around 3.5 pounds, slim their waist-lines and cut bad cholesterol – all without dieting.
Researchers who led the study said its results prove for the first time that people can lose weight without trying to.
“The weight reduction..when people ate less fat was remarkably consistent – we saw it in almost every trial. Those who cut down more on fat lost more weight,” said Lee Hooper from the University of East Anglia medical school, who led the work.
“The effect isn’t dramatic, like going on a diet,” she said, adding that the research specifically looked at people who were cutting down on fat, but didn’t aim to lose weight – so were continuing to consume a normal amount of food.
“What surprised us was that they did lose weight, their BMI (body mass index) decreased and their waists became slimmer,” Hooper said. The lower fat eaters also kept their weight down over at least seven years.
The review – commissioned by the WHO’s Nutrition Guidance Expert Advisory Group (NUGAG) after a request to update their guidelines on fat intake – will now form a crucial part of global recommendations, the researchers said.
Being overweight or obese increases the risk of many illnesses such as cancer, heart disease and stroke. Together, strokes, heart attacks and other cardiovascular diseases are the biggest killers worldwide and claim more than 17 million lives a year, according to the WHO.
More than half of Europeans are obese or overweight, and in America more than 35 percent of adults and almost 17 percent of children qualify as obese.
People are defined as overweight if their body mass index or BMI – a ratio of weight to height – is more than 25 kg per metre squared (kg/m2) and obese if it is more than 30 kg/m2.
Among the 73,500 people taking part in the studies analysed by Hooper’s team, there were varying ages and states of health. The researchers compared those eating less fat than usual and those eating their usual amount of fat, and measured the effect on weight and waistline after at least six months.
The results, published in the British Medical Journal, showed that eating less fat reduces body weight by 1.6 kg, cuts BMI by 0.56 kg/m² and reduces waist circumference by 0.5 cm.
Hooper’s team found that reductions in total fat intake were also linked with small but statistically significant reductions in cholesterol and blood pressure, suggesting a lower fat diet could have a beneficial effect on this heart risk factors.
Carolyn Summerbell of Durham University, who co-led the research, said the trick to slimming down and staying that way was to find a way to eat what you can stick to for life.
“Cutting down on fat will help,” she said, adding that this meant opting for low-fat yoghurts, skimmed milk and reducing intake of butter, cheese and fatty snacks like crisps and cakes. (Editing by xxxxxxxx)
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The research also suggests how ultrasound can accurately measure the type of fat associated with the biggest health risks.
“This research will be useful for judging the dangers for overweight or obese pregnant mothers. The results could also be helpful in measuring the success of strategies to address obesity,” said Professor Ralph Nanan from Sydney Medical School Nepean and the lead author of two studies outlining the findings.
The first study recently published in Obstetric Medicine, analysed over 9000 pregnancies and found that more than 50 percent of Australian pregnant women are either overweight or obese.
The study found that the risk of developing complications, such as hypertension or diabetes in pregnancy or the need for a caesarean section, increases with the level of obesity but that not all obese women are equally likely to develop these sorts of complications.
“What we found is that how the fat is distributed in the body is a significant factor when judging weight-related health risks. In this context fat around the inner organs, referred to as visceral fat, is more dangerous than peripheral fat, the fat around our extremities,” said Professor Nanan.
“While we might assume that someone with a big belly has a high level of visceral fat and someone with fat on their legs and bottom has high levels of peripheral fat, in a medical setting we need to make objective measures and not rely on impressions and this is especially true for pregnant women.”
“We need the most accurate diagnostic tool possible to decide if the fat on your belly is a sign of fat around your organs.”
In the second study led by Professor Nanan, published this week in the Australian New Zealand Journal of Obstetrics and Gynecology, the researchers from the University of Sydney and University of Melbourne addressed this problem by using ultrasound to measure abdominal fat thickness, also known as subcutaneous fat.
They analysed 1200 images of pregnant women, taken as a part of a routine ultrasound conducted midway through a pregnancy.
Subcutaneous fat is not exactly the same as visceral fat but it is a highly accurate indicator of its levels.
“We found that these simple, safe and inexpensive measurements gave us a much better predictor of obesity-related pregnancy outcomes than routinely used measures such as the Body Mass Index (BMI). The BMI is calculated by simply using a woman’s weight and height measurements,” said Professor Nanan.
The results mean maternal abdominal fat thickness can be used as a more accurate measure than those currently being applied to assess risks for overweight or obese mothers.
“This can help us with management of possible risk cases including judging whether and when to transfer a soon-to-be mum to a specialist birthing centre,” Professor Nanan said.
“Our current inability to more accurately predict levels of risk for weight-related conditions means we quite rightly err on the side of caution. Better information could mean pregnant women avoid an unnecessary intervention and would save money for the health system.”
The ultrasound method would also be useful to assess progress and health risks for people using diet or surgery to deal with overweight or obesity issues.
Both of the published studies have been supported by the Nepean Medical Research Foundation, the Australian Women and Children’s Research Foundation and the local Nepean community.
The researchers are currently confirming their new measure for obesity in pregnancy in a larger prospective study.
University of Sydney
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‘Tackling population fatness may be critical to world food security and ecological sustainability.’
OVERWEIGHT people are a threat to future food security, scientists say.
Increasing population fatness could have the same implications for world food energy demands as an extra 1 billion people, researchers say after examining the average weight of adults worldwide. Scientists from the London School of Hygiene and Tropical Medicine said tackling population weight was crucial for food security and ecological sustainability.
The United Nations predicts that by 2050 there could be a further 2.3 billion people on the planet and the ecological implications of the rising population numbers will be exacerbated by increases in average body mass, researchers said.
The world’s adult population weighs 287 million tonnes, 15 million due to being overweight and 3.5 million due to obesity, according to the study.
The data, collected from the UN and the World Health Organisation, shows that while the average global weight per person is 62 kilograms in 2005, Britons weighed 75 kilograms. In the US, the average adult weighed 81 kilograms.
Across Europe, the average weight was 70.8 kilograms compared with 57.7 kilograms in Asia. More than half Europe’s inhabitants are overweight (55.6 per cent) compared with only 24.2 per cent of Asians. Almost three-quarters of North Americans are overweight.
The researchers say the energy requirement of humans depends not only on numbers but average mass. ”Tackling population fatness may be critical to world food security and ecological sustainability,” they wrote.
Professor Ian Roberts, who led the research, said: ”Everyone accepts that population growth threatens global environmental sustainability – our study shows that population fatness is also a major threat. Unless we tackle both population and fatness, our chances are slim.”