Sunday 26 June 2005

Pic of the day: "What do they eat to grow up like that?" Fat, and lots of it. Women sequester some of their fat in humps on their chest and hips, where it can be used later for pregnancy and lactation, or to temporarily lower the IQ of passing males. It still counts toward their body mass index, though. (Screenshot from the anime DearS.

Fat – or perhaps not

In the June issue of Scientific American, there is an interesting article about the "epidemic of obesity" which we have heard so much about lately. The article, which is based on arguments of scientists entirely outside the medical profession, argues that obesity is no big deal and that moderate overweight is good for you.

By going through several large studies, they have found that the conclusions are not supported by the numbers. On the contrary, moderately overweight people (body mass index 25-30) have a lower mortality than those of "healthy" weight (18.5-25). The obese have a higher mortality, but it is sinking. Life expectancy is not falling back, but still growing. Blood pressure in obese people today is lower than in normal-weight people only a few decades ago, indicating that their lifestyle is overall more healthy. Furthermore, they claim, there is no positive value in whipping up a frenzy about the weight gain, because it can not be avoided and worrying people will just make them fatter. There is no method to reduce body mass with more than 5% on a lasting basis, after all, and weight is mostly genetic. The weight reduction industry is sponsoring the science so it is inherently dubious, and in the end they are the only ones to profit from the mass hysteria about obesity.

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One of the nice things about Scientific American is that it allows some debate (just not by people who doubt evolution or man-made mass extinction). And debate is the main value of this article. As mentioned, none of them belong to or is associated with the medical profession, and it shows. They cheerfully ignore the fact that excess fat degrades the body in ways that are well known and documented. It is not a secret, even to the informed layman, that obesity causes a wide range of health problems from knee pains through diabetes to heart attacks.

What has happened, however, is that the treatment of these illnesses has been improved dramatically. In the past, you suddenly got a heart attack and within a week you were dead. That was that. Today, heart problems are usually diagnosed years before they would have been fatal, and preventive medication or surgery is applied. For this reason, mortality from classic infarcts and atherosclerosis has tumbled. People still get sick, and the cost to society is enormous as more and more resources are funneled into treating lifestyle diseases. The USA, that lighthouse of obesity, also stands out in the extreme medical expenses compared to life expectancy. None of this is given any attention at all in the article.

Nor is it a defensible statement that "no safe and widely practical methods have been shown to induce long-term loss of more than about 5% of body weight". Vegetarianism is safe, indeed safer than meat eating, and both practical and practiced by lots of people. It is certain to keep the fat away, especially if combined with light exercise such as walking or doing housework. In fact, almost any change of diet away from the American standard is likely to improve your health. If you copy the cooking of almost any first- or second-world country, you are likely to notice improved health. But the opposite is true, of course. The world copies the American Way of Overeating, binging on supersized burgers and cola. Norwegians are still those vaunted 5% slimmer than our American friends and relatives. Do you really honestly tell me that this comes from a mass exodus of fat people during those years of going west?

"There are three kinds of lies: Lies, damned lies, and statistics." This article is based entirely on statistics. And it shows.

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That said, it was about time someone asked who set the limits for overweight, and why. Sadly this article doesn't really answer that. It strongly hint that the government agencies and the medical profession in general are in the pockets of the industry, something I call a cookie- cutter leftist conspiracy theory. Of course, just because it is a conspiracy theory doesn't mean it can't be true. There are conspiracies in the world, after all, only not nearly as much as simple minds believe. The other theory espoused seems more likely, namely that making alarmist headlines ensures government funding.

But personally I suspect that the choice of setting the limit for overweight so low is the widely recognized principle: "First, do no harm." If there is doubt about whether a higher weight may be dangerous to some patients, but no doubt that a lower weight is harmless, then you would set the limit a bit lower out of cautiousness. Since there are no known mechanism by which a body mass index over 25 would benefit people, it makes sense to set the limit lower. But in light of the new statistics, or rather the new reading of them, perhaps it is time to look over this again.

One of the most surprising findings was that overweight protects against lung cancer. It does seem to promote colon cancer, but lung cancer is the cause of more deaths so this would influence the statistics heavily. The protection seems to extend to all levels of overweight, but of course the outright obese have other problems that counterbalance it. The lung cancer protection of fat would then be a major cause for the new conclusion, that moderate overweight is better than the previously declared "healthy weight". The article explicitly states that this was even after correction for smoking.

I doubt this, but it is impossible to say for sure without a very thorough research. What I believe is that the demonizing of smokers in recent years has caused under-reporting. People may actually forget that they have been smoking for parts of their life. After all, it is in the past, and if God has forgotten my sin, why shouldn't I? Or they may think, reasonably, that they did not smoke so much that it should be called smoking. They just took a cigarette now and then in good company or on special occasions. Surely that wouldn't be smoking? If they said they were smoking, they would distort the statistics, right? It's a good bet that such questionnaires, like so many other, are not detailed enough to fit in such occasional smokers. However, their body remembers. Putting on weight that lasts is a long process, and if you smoked in the past or smoke occasionally, it will still be reflected in your lower weight ... and in your lungs.

I'd like to see whether the statistics were checked for this, before I fully believe that overweight is good for your lungs. But who knows? Recently it has been discovered that small amounts of alcohol is actually good for your heart, and a plausible biochemical model for explaining it has been published (also in Scientific American).

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That said, this very objection implies that a body mass index of below 25 is not natural for most people, if they need to smoke periodically to stay below it. I know that for most of my own adult life, my BMI has hovered around that level. At no point was I visibly "fat". The midlife bulge was due largely to undertrained gut muscles. Once I pull my guts in, there is no place on my body you could point and cry "fat!". This is probably the case for a lot of us, although women tend to have less fat around their intestines and more on their hips, which are probably harder to pull in when people look at you. (Although I understand certain clothes have a similar effect for them.) I think perhaps the number 25 was chosen partly for convenience, and a more natural number would be like 27 or 28. (Due to the way BMI is calculated, even such a change would probably be visible on many people.)

Men have a higher natural BMI, because BMI is based on weight (weight in kilograms divided by the square of height in meters). Our hormones make us add and keep muscle mass more easily by everyday activities. And muscle mass are not only "not fat", it is heavier than fat, and so it gives an extra false positive on the BMI. On the other hand, women generally store fat in a safer way, so even if they are visibly fatter they are less harmed by it. This is the rationale between having the same BMI limits for both sexes. This is however only a general rule. Some women store fat on their upper bodies, and should have had a lower BMI limit. Some men are more heavily muscled than others, and should have had a higher BMI. Statistics only give averages. To know what is good for you, you need a thorough check by medical professionals who don't have an economic interest in lying to you. This is possible, but probably not common.

Hopefully these random thoughts may have alerted you to some of the reality around you on this topic. The article had that effect on me, at least. So despite its dubious worth as medical science, it still had its value.