Quotulatiousness

August 21, 2013

Obesity – it’s not just for humans any more

Filed under: Health, Science — Tags: , , — Nicholas @ 09:01

We’re constantly being barraged with public service announcements from public figures that we all eat too much, exercise too little, and as a result society has a (sorry) growing obesity problem. However, as David Berreby points out, it’s not as simple as that:

Consider, for example, this troublesome fact, reported in 2010 by the biostatistician David B Allison and his co-authors at the University of Alabama in Birmingham: over the past 20 years or more, as the American people were getting fatter, so were America’s marmosets. As were laboratory macaques, chimpanzees, vervet monkeys and mice, as well as domestic dogs, domestic cats, and domestic and feral rats from both rural and urban areas. In fact, the researchers examined records on those eight species and found that average weight for every one had increased. The marmosets gained an average of nine per cent per decade. Lab mice gained about 11 per cent per decade. Chimps, for some reason, are doing especially badly: their average body weight had risen 35 per cent per decade. Allison, who had been hearing about an unexplained rise in the average weight of lab animals, was nonetheless surprised by the consistency across so many species. ‘Virtually in every population of animals we looked at, that met our criteria, there was the same upward trend,’ he told me.

It isn’t hard to imagine that people who are eating more themselves are giving more to their spoiled pets, or leaving sweeter, fattier garbage for street cats and rodents. But such results don’t explain why the weight gain is also occurring in species that human beings don’t pamper, such as animals in labs, whose diets are strictly controlled. In fact, lab animals’ lives are so precisely watched and measured that the researchers can rule out accidental human influence: records show those creatures gained weight over decades without any significant change in their diet or activities. Obviously, if animals are getting heavier along with us, it can’t just be that they’re eating more Snickers bars and driving to work most days. On the contrary, the trend suggests some widely shared cause, beyond the control of individuals, which is contributing to obesity across many species.

Such a global hidden factor (or factors) might help to explain why most people gain weight gradually, over decades, in seeming contradiction of Bloomberg’s thermodynamics. This slow increase in fat stores would suggest that they are eating only a tiny bit more each month than they use in fuel. But if that were so, as Jonathan C K Wells, professor of child nutrition at University College London, has pointed out, it would be easy to lose weight. One recent model estimated that eating a mere 30 calories a day more than you use is enough to lead to serious weight gain. Given what each person consumes in a day (1,500 to 2,000 calories in poorer nations; 2,500 to 4,000 in wealthy ones), 30 calories is a trivial amount: by my calculations, that’s just two or three peanut M&Ms. If eliminating that little from the daily diet were enough to prevent weight gain, then people should have no trouble losing a few pounds. Instead, as we know, they find it extremely hard.

Many other aspects of the worldwide weight gain are also difficult to square with the ‘it’s-just-thermodynamics’ model. In rich nations, obesity is more prevalent in people with less money, education and status. Even in some poor countries, according to a survey published last year in the International Journal of Obesity, increases in weight over time have been concentrated among the least well-off. And the extra weight is unevenly distributed among the sexes, too. In a study published in the Social Science and Medicine journal last year, Wells and his co-authors found that, in a sample that spanned 68 nations, for every two obese men there were three obese women. Moreover, the researchers found that higher levels of female obesity correlated with higher levels of gender inequality in each nation. Why, if body weight is a matter of individual decisions about what to eat, should it be affected by differences in wealth or by relations between the sexes?

January 8, 2013

Obesity meta-study challenged the media narrative

Filed under: Government, Health, Media, Science — Tags: , , , — Nicholas @ 10:00

In sp!ked, Timandra Harkness explains why the publication of “Association of All-Cause Mortality With Overweight and Obesity Using Standard Body Mass Index Categories” in the Journal of the American Medical Association (JAMA) got such a strongly negative reaction from the media and various government spokespeople:

The reason this unassuming paper drew howls of outrage was the same as the reason the benefits of moderate alcohol intake are never noted without criticism: it spoils the headline health message that Fat is Bad.

Even worse, it blows the cover on the great myth — that an epidemic of Bad Fatness is sweeping the developed world. By including the dangerously obese, the innocuously tubby and the healthily plump in one category, ‘overweight including obese’, 60 per cent of the English population are labelled as potentially At Risk.

Being At Risk means these people need guidance and protection from their own vulnerable state, from the temptations of our obesogenic world and the frailties of their own sugar-addicted brains. At such a time of national peril, no measure is too extreme.

But less than a quarter of English adults are obese, according to new figures released just before Christmas, a fraction almost unchanged since 2007. And the ‘morbidly obese’ category — BMI over 40, the ones for whom it really might be worth shedding a few pounds, medically speaking — also remains steady since 2009 at 2.5 per cent of the UK population.

If only one in 40 of us is in significant weight-related danger, why do the other 97.5 per cent of us need to be protected by the state against sugary cereals and fizzy drinks? Could it be because only a few of us have fallen, but all of us are in peril? Weak, foolish and easily led astray, we need to be frightened back on to the right path. Thus Tam Fry, spokesman for the National Obesity Forum — who has called for children to be monitored from birth for signs of obesity — told the Independent: ‘If people read this and decide they are not going to die… they may find themselves lifelong dependents on medical treatment for problems affecting the heart, liver, kidney and pancreas — to name only a few.’

So there we have it. Those extra post-Christmas pounds aren’t going to kill you. If you’re approaching an age at which there’s any real prospect you will die, they probably have a tiny protective effect. But if you’re told the truth, suggest the obesity obsessives, you’ll gorge yourself into a disgusting ball of flab.

January 2, 2013

Don’t let your BMI scare you (too much)

Filed under: Health, Media — Tags: , , , , — Nicholas @ 10:47

A quick reminder that the Body Mass Index (BMI) is more a convenient mathematical trick than an actual healthy weight guideline:

In a finding that could undermine many New Year’s resolutions, a new government study shows that people who are overweight are less likely to die in any given period than people of normal weight. Even those who are moderately obese don’t have a higher-than-normal risk of dying.

Being substantially obese, based on measure called body mass index, or BMI, of 35 and higher, does raise the risk of death by 29%, researchers found.

But people with a BMI of 25 to 30 — who are considered overweight and make up more than 30% of the U.S. population — have a 6% lower risk of death than people whose BMI is in the normal range of 18.5 to 25, according to the study, being published Wednesday in the Journal of the American Medical Association.

People who had a BMI of 30 to 35 — considered the first stage of obesity — had a 5% lower risk of dying, but those figures weren’t considered statistically significant.

In other words, a few extra pounds are not going to threaten your life (a lot of extra pounds might). In the western world, few of us have the kind of jobs that require much in the way of physical exertion and we also have both relatively low food prices and much greater access to calorie-dense food. Our parents tended to have jobs that required more physical effort and their access to food was not as great as ours (they were less wealthy overall, and didn’t eat at restaurants or fast food joints as often as we do). Two otherwise positive trends that combine to produce a less-positive result on the scales.

Earlier discussion of the limitations of BMI as a guideline here, here, here, and here.

July 10, 2012

BMI: Badly Misleading Indicator

Filed under: Health, Media — Tags: , , , — Nicholas @ 09:04

Lewis Page explains why being too thin is a bad idea health-wise:

Yet another study has shown that the so-called “obesity” epidemic sweeping the wealthy nations of the world has been massively over-hyped, as new results show that is is far more dangerous to be assessed as “underweight” than it is to be assessed even as “severely obese” — let alone merely “obese” or “overweight”.

“There is currently a widespread belief that any degree of overweight or obesity increases the risk of death, however our findings suggest this may not be the case,” says health prof Anthony Jerant, lead author of the study. “In the six-year timeframe of our evaluation, we found that only severe obesity was associated with an increased risk of death.”

Most statistics in this field are still based on the now widely discredited Body Mass Index (BMI) system, under which people are assessed as “underweight”, “normal”, “overweight”, “obese” or “severely obese”. BMI, devised in the early 19th century by an obscure Belgian sociologist without medical qualifications, copes poorly with increases in height as it assumes the human body will scale up in mass in proportion to the square of height — which doesn’t allow for the fact that bodies are three dimensional — and further fails to allow for the greater cross-sectional area needed in supporting structures to carry increasing weights.

June 19, 2012

British “researchers” call for starvation diets to meet carbon targets

Filed under: Britain, Environment, Health — Tags: , , — Nicholas @ 11:04

There’s only so much “mad” you can tolerate in the ranks of your “scientists”, and these guys are more than a bit over-the-top:

A famous mad professor who has previously called for Britons to starve their children into dwarfism so as to ease strains on the planetary ecosystem has reiterated his arguments, this time insisting that the amount of surplus flab carried by the human race will soon be equivalent to having another half-a-billion people on Earth.

Regular readers will be familiar with Professor Ian Roberts of the London School of Hygiene and Tropical Medicine already: he and his colleague Dr Phil Edwards wrote a paper in 2009 in which they suggested that it would be a good idea for Britons and Americans to model their diet and physique on that of the “lean” Vietnamese, as this would assist in such things as meeting British government carbon pledges. Lightweight Vietnamese people, according to the two scientists, not only need less food but use less energy to move themselves around.

Unfortunately, as we pointed out at the time, this would not merely have been a matter of Britons shedding some flab. In order to match the Vietnamese on weight, Brits would also have to lose four inches or so of height. Extrapolating from Roberts’ and Edwards’ figures, in fact, the people of the UK would need to shrink to a Hobbit-like stature barely over three feet to meet the more ambitious governmental carbon goals.

Oh, and in case you still think BMI has any scientific validity, here’s your disillusionment of the day:

Unfortunately the entire edifice of their argument is based on the long-discredited Body Mass Index (BMI), a frankly bizarre method of assessing how fat people are which was developed by an obscure Belgian social scientist without any medical qualifications in the early 19th century. The BMI assumes that healthy human mass goes up in proportion to the square of height, a patently absurd suggestion given that human bodies are three-dimensional rather than flat 2D shapes. All other things being equal a human’s weight should go up related to the cube of height — and indeed they aren’t equal. Any engineer will point out that cross-sectional area in support structures (feet, leg bones etc) needs to go up in direct proportion to weight carried, adding still more heft than a cube law would as height goes up. This is why elephants are not simply scaled-up dogs, and dogs are not simply scaled-up insects — they have proportionally thicker legs and other supporting structures and come out much heavier.

As one would expect, then, it has been confirmed by several recent studies among the taller populations of the modern-day developed nations that a BMI assessment of “overweight” should really be assessed as normal or healthy, while the previous “normal” range ought in fact to be dubbed “underweight”, as it has negative health consequences similar to being “obese”.

By suggesting that the human race — including the taller peoples — needs to shift into the outmoded BMI “normal” range, Roberts and his fellow public-health experts are advocating a course which would cause more health problems: scarcely what they are paid to do.

October 18, 2011

Politicians should stop lecturing us about our “obesity epidemic”

Filed under: Britain, Government, Health, Media — Tags: , , , — Nicholas @ 09:32

Rob Lyons in the Yorkshire Post:

I would argue that the obesity panic is greatly exaggerated, that the “cure” for it doesn’t work, and that it usually gets promoted by politicians who have no better way to justify their existence.

For starters, obesity rates have stopped rising for adults, and are actually falling for children. The latest figures from the Health Survey for England, the best source of information we have, show that in 2009, 22.1 per cent of men were obese — compared to 24.1 per cent in 2008; for women, the new figure was 23.9 per cent, as against 24.9 per cent in 2008.

In 2004, 19.4 per cent of boys aged two to 15 were regarded as obese; in 2009, that figure was down to 16.1 per cent. The equivalent figures for girls were 18.5 per cent (2004) and 15.3 per cent (2009).

Even then, what the medical profession regards as obesity and what we commonly recognise as obesity are two different things. About one in four adults is classed as obese.

Now, think about your workmates and friends. Would you really regard a quarter of them as obese? I’ll bet few of them match up to the typical picture that accompanies every story about obesity: a morbidly obese person, whose clothes are straining to hold in their tummies. Such very overweight people only make up about two per cent of the population.

In truth, distinctions between normal weight, overweight and obesity are pretty arbitrary lines, based on something called body mass index (BMI) — that’s your weight in kilos divided the square of your height in metres. BMI is not a particularly good predictor of health, except at the extremes. Those who are mildly obese have much the same life expectancy and health outcomes as those who are normal weight. Being a little underweight is almost certainly worse for you than being mildly obese.

March 15, 2011

“Obesity crusaders” use “inherently flawed instruments, such as BMI and apple-body shapes, to misinform the public”

Filed under: Government, Health, Media — Tags: , , , — Nicholas @ 12:50

Patrick Basham and John Luik address the manifest failings of the public health crusade against obesity:

Since the anti-obesity campaign is allegedly motivated by scientific findings, it would seem reasonable and prudent to make doubly sure that those claims are factual and trustworthy. Yet, we continue to find that the case against obesity is significantly flawed. Not only are the claims of an obesity epidemic often wildly exaggerated, but the science linking weight to unfavourable mortality outcomes is also frequently nonexistent or distorted.

[. . .]

As Danesh suggests, other researchers have suggested concentrating on a measurement of the waist alone, while many cling to BMI, which calculates obesity based upon a weight-to-height ratio. Because of its easy applicability, BMI is universally used in officially defining obesity, despite its manifest shortcomings. The BMI is wholly arbitrary and has no scientifically valid connection with mortality.

“Obesity crusaders” are what we call the individuals who manufactured the obesity-epidemic story in the first place and continue, through application of inherently flawed instruments, such as BMI and apple-body shapes, to misinform the public. They are a relatively small group of public-health officials in the US, the UK, the EU, and the World Health Organisation, assorted academics (very many with close ties to the weight-loss and pharmaceutical industry), the International Obesity Task Force, and a collection of so-called public-interest science groups.

How are these obesity crusaders reacting to the unambiguously good news published in The Lancet? Surely, they rejoice at the fact there is one less thing for a health-conscious population to fret over? No, they are not in celebratory mood. Quite the contrary. The obesity crusaders did not waste any time on the New Good News; after all, the Old-Time Religion continues to serve them so well.

It gets worse for the “fat=early death” meme:

There is little credible scientific evidence that supports the claims that being overweight or obese leads to an early death. For example, Katherine Flegal of the Centers for Disease Control and Prevention found that in the US population there were more premature deaths among those who are normal weight than those who are overweight. Indeed, in this study, Americans who were overweight were those most likely to live the longest.

In the American Journal of Public Health, Jerome Gronniger found that men in the “normal” weight category exhibited a mortality rate as high as that of men in the moderately obese category; men in the “overweight” category clearly had the lowest mortality risk.

July 29, 2010

Replacing one impossible ideal with another

Filed under: Britain, Health, Media — Tags: , , , — Nicholas @ 09:23

Colby Cosh linked to this Guardian article, saying “I’m afraid she’s right. ‘Thin’ is something every girl can at least strive for. Only God can make Christina Hendricks.”

When it comes to the ideal female body-shape the pipe cleaner is out, the hourglass is in — or at least it will be if the new equalities minister, Lynne Featherstone, manages to chisel out her will on the perfect body image.

“In the autumn the minister will convene the first of a series of roundtable discussions with members of the fashion industry, including magazine editors, models and advertisers, to discuss how to boost body confidence among the young,” the Sunday Times reported yesterday.

One might think that one of the first steps to boost such confidence might be to abolish school weigh-ins and make puppy fat a normal rite of passage rather than the subject of a health warning via the National Child Measurement Programme. (Can any woman think of anything more likely to have produced a fear of being on the chunky side than turning up to school one morning and being plonked on a set of scales?)

While I’m happy to have any excuse to post a photo of the delightful “YoSaffBridge”, this is another example of Nanny State thinking: (some) women have body image issues, therefore we must spring into action and fix it.

Rather than replacing the old impossible images with new impossible images (as the creative director of Harper’s Bazaar pointed out, the fashion industry exists to create the fantasy you’ll never live up to) an equalities minister should throw out all notions of obsessing about feminine beauty and concentrate on helping young girls think about the size of their achievements rather than the flatness of their navels, and the scale of their ambitions rather than — in Joanie’s case — the rather spectacular power of their bosoms.

March 11, 2010

Researchers say that fat may actually be a flavour

Filed under: Health — Tags: , — Nicholas @ 07:13

This may provide some clues to obesity, as tests show that some people can detect fat at much lower concentrations . . . and therefore consume less:

It’s a theory set to confirm why humans are so fond of fatty foods such as chips and chocolate cake: in addition to the five tastes already identified lurks another detectable by the palate — fat.

“We know that the human tongue can detect five tastes — sweet, salty, sour, bitter and umami (a savoury, protein-rich taste contained in foods such as soy sauce and chicken stock),” Russell Keast, from Deakin University, said Monday.

“Through our study we can conclude that humans have a sixth taste — fat.”

Researchers tested 30 people’s ability to taste a range of fatty acids in otherwise plain solutions and found that all were able to determine the taste — though some required higher concentrations than others.

[. . .]

The results, published in the British Journal of Nutrition, have not definitively classified fat as a taste but Keast says the evidence is strong and mounting.

For something to be classified as a taste there needed to be proven receptor mechanisms on taste cells in the mouth, he said.

October 26, 2009

A partial answer about increasing body weight

Filed under: Economics, Health — Tags: , , — Nicholas @ 00:20

Here are some useful images that help to explain why North Americans have been getting heavier over the last few decades:

Over the past few decades, portion sizes of everything from muffins to sandwiches have grown considerably. Unfortunately, America’s waistbands have reacted accordingly. In the 1970s, around 47 percent of Americans were overweight or obese; now 66 percent of us are. In addition, the number of just obese people has doubled, from 15 percent of our population to 30 percent.

While increased sizes haven’t been the sole contributor to our obesity epidemic, large quantities of cheap food have distorted our perceptions of what a typical meal is supposed to look like. These portion comparisons, adapted from the National Heart, Lung, and Blood Institute’s (NHLBI) Portion Distortion Quiz, give a visual representation of what sizes used to be compared to what they are today.

Pizza_then_and_now
Bagels_then_and_now

H/T to John Scalzi for the link.

August 8, 2009

Dieting and obesity

Filed under: Health — Tags: , , — Nicholas @ 00:13

Megan McArdle had an interesting-but-lengthy post earlier this week on obesity and both the scientific and political issues surrounding it:

I don’t agree with Paul Campos about everything, but I do agree with some of his core propositions:

  • Study after study shows that most people are unable to lose more than a small percentage of their body weight and keep it off without major surgery
  • There is evidence to show that this is physiologic rather than pyschological — it is nearly impossible for very heavy people to simply “eat less and exercise more” to a “normal” weight (given that 2/3 of the country is overweight or obese, normal weights, aren’t.)
  • The fact that this often operates through the appetite system does not mean it’s “all in their heads” or a lack of willpower. Appetite is a signal as powerful as thirst or pain. Most people can’t ignore it.
  • The largest environmental determinant of this trend is probably simply cheaper, tastier calories, which will be very hard to reverse

[. . .]

This really is a pattern that you see over and over again in obesity research. It’s as if researchers are terrified to say anything that might be viewed as giving people license to get fat. The CDC researcher who sharply revised downward the estimates of deaths from obesity, finding that overweight was actually healthier, fell all over herself proclaiming that of course, this didn’t account for quality of life. Because we know that a woman who weighs 160 pounds couldn’t possibly have a decent quality of life . . . ?

[. . .]

I know, I know . . . it’s for the children! I am very fond of children. But I do not actually think that they are some sort of master race in whose name anything at all can be justified. And if I did, I’d be a lot more worried about, oh, abortion, than McDonalds ads.

Two final points. Everyone likes to focus on their favorite boogeymen. To read a left-wing blog, you’d think that about 95% of the leading cause of obesity was agribusiness, chain restaurants, and automobiles. To read a right-wing paper, it’s all the infamous lack of self-control displayed by the poor.

But in fact, most of the things effecting kids are side effects of other efforts a lot of people are rather fond of. Processed foods and chain restaurants have exploded in the last two decades because Mom spends more time outside the home, generating more market income, and less time for home cooked meals. Kids exercise less not because crime is higher, or even because we’ve become more suburban, but because they’re no longer allowed to operate unsupervised until they’re quite old, and Mom and Dad both work. Schools don’t have P/E because they’re using the time to teach kids to read. Maybe those were bad tradeoffs. But they’re not irrational tradeoffs, and switching them back is not costless.

One thing Megan doesn’t touch on in the post (although she had done in earlier posts on this topic) is that metabolic changes over individuals’ lifetimes can actively sabotage good intentions on maintaining a given weight. Up until my late 20s, I could lose weight just by thinking about it, and then suddenly in my early 30s, I discovered that taking weight off was something that now needed a more conscious effort. Now I’m finding it even tougher to manage my weight (and also harder to make and take advantage of opportunities to get some exercise). My innate laziness and enjoyment of good food and good wine can usuallyalways overwhelm any urge to go do something healthy instead.

And no, I didn’t copy the entire post . . . there’s lots more, and it’s all worth reading.

« « This looks like a lot of fun| Yesterday’s menu: random thunderstorms » »

Powered by WordPress