EXERCISE AND OBESITY: CHICKEN OR EGG?
Are people fat because they exercise less or do they exercise less because they are fat? The study below cannot not tell us. But why bother with proof when you KNOW what is going on? A pity that what people KNOW is often not true
The risk of children becoming obese could be halved with 15 extra minutes of moderately vigorous exercise each day, study results have suggested. All that is needed is a short game of football or a walk to school brisk enough to get slightly out of breath. The effects are greater in boys than in girls, but both sexes benefit. The findings point to a lack of exercise, rather than gluttony, as the key to obesity in young people. Researchers were surprised to find that boys have just 25 minutes of activity each day on average, and girls only 16 minutes.
The data comes from the Children of the 90s project, which has followed a group of children born in Avon in the 1990s. The Avon Longitudinal Study of Parents and Children is one of the biggest and most ambitious cohort studies ever attempted and is producing some of the best evidence on the effects of diet and lifestyle on disease. Researchers fitted 5,500 children aged 12 with activity meters to measure how much exercise they took. The children wore the meters around their waists, taking them off only to sleep, bath or swim. Their body fat was measured using an X-ray emission scanner, which can distinguish between fat and muscle. The results are published in PLoS Medicine.
Professor Chris Riddoch, of the London Sport Institute at Middlesex University, one of the project leaders, said: "We know that diet is important, but what this research tells us is that we mustn't forget about activity. It's been really surprising to us how even small amounts of exercise appear to have dramatic results."
The boys who took the most vigorous activity were more than 30 times less likely to be obese than those who took the least. An extra 15 minutes a day of moderate and vigorous physical activity halved the risk of obesity. Among girls the effects were less dramatic, but still significant. The most active fifth of girls reduced their risk of obesity by two thirds compared with the least active fifth.
Professor Andy Ness, of the University of Bristol, said that the most important activity was the kind that got the children slightly out of breath, or in a sweat. "Recommending an extra 15 minutes of vigorous activity a day may not sound very much, but it is actually double what the average 12-year-old girl does," he said. "In the context of what they are doing, it is quite a lot."
Why the effects should be so much greater in boys remains puzzling. "It could be physiological differences but I think that's unlikely," Professor Ness said. "The other possibility is that boys and girls use activity differently. Boys tend to use activity as the main weight control mechanism, while girls tend to control their weight by eating less." He said that surveys and food production statistics suggested that total calorie intakes had not increased. Yet obesity was rising, so it was reasonable to suggest that this was the result of burning less energy. "Lots of opportunities for activity are factored out of children's lives these days," he said. "There are more sedentary opportunities - sitting in the car, watching television, playing computer games. There's less walking to school, and when they get home Mum and Dad don't want them wandering off into the woods or playing in the streets."
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Organic food is no better
ORGANIC food has no nutritional benefit over regular products despite the belief it is healthier and costs much more, scientists say. Shoppers who buy organic often believe they are getting nutritionally superior products - but experts say there is no evidence to support this claim. Research shows most fruit and vegetables on sale in Australia have the same levels of nutrients and no traces of pesticides, regardless of whether they are organic or not.
Jennie Brand-Miller, professor of molecular and microbiological sciences at Sydney University, says many consumers are paying more, mistakenly believing that organic is better. "We need to get the message out there that non-organic produce is genuinely good quality,'' she said. "We have got a lot to gain from eating fresh fruit and vegetables so the best message is eat as much as you like.''
Organic produce is usually more expensive than conventional foods - sometimes double in price. Consultant dietitian Shane Landon said Australian food standards were high, ensuring all produce was safe to eat. "If people do want to pay a bit more to buy organic and have an orange that looks a bit funny that's fine, but I'm not convinced it's healthier,'' he said. A consumer would have to eat truckloads of non-organic food to accumulate any meaningful amount of pesticides or chemicals in their body, he said. And analysis shows some organic produce does contain residual pesticides.
Suggestions of high levels of hormones in chicken have been proven to be an urban myth, as oestrogen has been banned as an ingredient in chicken feed in Australia since the 1960s.
Advocates prefer to eat organic food because it is likely to have travelled a shorter distance from harvest to shop than its non-organic counterparts, therefore making it more environmentally friendly. Professor Brand-Miller said there was some evidence that organic food, which should be produced without the use of pesticides and artificial chemicals, might be kinder to the planet in the long-term. Erin Pearson, a speech pathologist from Oatley, has bought organic food in the past but didn't notice any difference. "I feel the normal stuff is just as good and organic does tend to be more expensive,'' she said
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Just some problems with the "Obesity" war:
1). It tries to impose behavior change on everybody -- when most of those targeted are not obese and hence have no reason to change their behaviour. It is a form of punishing the innocent and the guilty alike. (It is also typical of Leftist thinking: Scorning the individual and capable of dealing with large groups only).
2). The longevity research all leads to the conclusion that it is people of MIDDLING weight who live longest -- not slim people. So the "epidemic" of obesity is in fact largely an "epidemic" of living longer.
3). It is total calorie intake that makes you fat -- not where you get your calories. Policies that attack only the source of the calories (e.g. "junk food") without addressing total calorie intake are hence pissing into the wind. People involuntarily deprived of their preferred calorie intake from one source are highly likely to seek and find their calories elsewhere.
4). So-called junk food is perfectly nutritious. A big Mac meal comprises meat, bread, salad and potatoes -- which is a mainstream Western diet. If that is bad then we are all in big trouble.
5). Food warriors demonize salt and fat. But we need a daily salt intake to counter salt-loss through perspiration and the research shows that people on salt-restricted diets die SOONER. And Eskimos eat huge amounts of fat with no apparent ill-effects. And the average home-cooked roast dinner has LOTS of fat. Will we ban roast dinners?
6). The foods restricted are often no more calorific than those permitted -- such as milk and fruit-juice drinks.
7). Tendency to weight is mostly genetic and is therefore not readily susceptible to voluntary behaviour change.
8). And when are we going to ban cheese? Cheese is a concentrated calorie bomb and has lots of that wicked animal fat in it too. Wouldn't we all be better off without it? And what about butter and margarine? They are just about pure fat. Surely they should be treated as contraband in kids' lunchboxes! [/sarcasm].
Trans fats:
For one summary of the weak science behind the "trans-fat" hysteria, see here. Trans fats have only a temporary effect on blood chemistry and the evidence of lasting harm from them is dubious. By taking extreme groups in trans fats intake, some weak association with coronary heart disease has at times been shown in some sub-populations but extreme group studies are inherently at risk of confounding with other factors and are intrinsically of little interest to the average person.
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