I recently published a post called “How Do We Know What We Know“?  I think it’s important that we think about how we come by the knowledge that we use to manage our lives.

Some people believe what they are told; “I read it in the newspapers”, “I saw it on TV”, “It must be true”.

Some people believe what they are told by authorities: their doctor, religious leader, etc.  Some people work off of a gut feeling, and some trust scientists.

But what is science?

What it isn’t is a bunch of (mostly) men in white coats with clip boards peering into microscopes and test tubes.

Science is a process of coming to know: of justifying a belief.

Beside me as I write I have what Brits call a torch and Americans call a flashlight. It doesn’t work and I want to know why.  My guess is that the battery is flat, so I take out the old battery, shove in a new one from my drawer, and the torch lights up.  That, in a nutshell, is the whole scientific process.

In science we start with a problem (torch doesn’t work); we form an hypothesis as to what the cause of the problem is (formally, according to Wikipedia, an hypothesis is a “proposed explanation for a phenomenon”.  Or a guess as to what is causing the problem).  We then design an experiment to test the hypothesis (hypothesis is that the battery is flat; experiment is to replace old battery with a new one.  If the torch then works we will declare that our hypothesis was the correct one).

There are a few problems with this experiment.  What if the problem wasn’t a flat battery, but a loose connection, and that taking one battery out and putting another back (or even the same one back) restored the connection?  Then we would have a “false positive”.  And we’d probably chuck away a perfectly good battery (and the torch would probably fail again next time it was shaken, and we might decide it was going through batteries too fast and chuck the torch out as well as the batteries.)

So to make the scientific process a bit more likely to produce good and useful knowledge, we come up with a whole set of hypotheses, and try to design experiments to test all of them.  For instance, hypotheses for our non-functioning torch might be:

  1. Flat battery
  2. Dead bulb
  3. Loose connection
  4. Alien invaders have stopped electricity working on earth.
  5. etc.

If we have an electric meter or tester we can use it to measure a brand new battery, straight out of its packet.  If that works then we know that the tester is working, and we can also rule out hypothesis number 4.  We can then use the tester on the battery.  We may need to test the battery and the bulb, and the connections, because the problem might be 1, 2, or 3, or any combination of the three variables (or four variables if we haven’t yet ruled out the alien invasion).

I’m sure that I am labouring the point, and that you get it by now.  But you may also be getting a sense that, to an outsider, science looks glamorous while actually it involves a lot of care and pains-taking step-by-step rigour.

In the science of nutrition, as in all other science, when we do experiments we need to “control” for all the variables.  If we think that eating chocolate is what is making someone fat we could take two groups of people, feed one group chocolate and the other not, and measure them.  But to be absolutely sure the problem is the chocolate, the two groups must eat exactly the same apart from the chocolate.  And exercise the same, and sleep the same, and drink the same, and live at the same altitude (I’ve just got back from a week in the rocky mountains: you’d be amazed at the difference it can have on you; even how often you need to wee!)

So, anyway, that’s what science is: it’s just a way of thinking about solving problems, of producing knowledge.

But here’s an interesting thing: it’s the science of finding things that will make people well.  On the face of it, if you developed a pill that stopped people getting smelly feet you might think you’d get a large group of people who have smelly feet, divide them into two groups, give one group the pill, the other group no pill, and see how smelly the feet were of the two groups.

But that’s not what pill researchers do.

They make a second pill that looks exactly the same as the first pill, but which does absolutely nothing.  It’s probably just made of chalk.  And no one knows which pill is which (except the people designing the research).  In particular, neither the folks taking the pills know which is which, nor do the folks handing out the pills.  This is called a “double-blind” trial and it is to prevent the outcome being influenced by the placebo effect and researcher bias.  The placebo effect is when people who are given the “sham” pill, but who believe it to be real, get better anyway.

Very many scientists tend to dismiss all sorts of things that are outside their paradigm as “just the placebo effect”.  But hang on … are you telling us that just because people believe they are getting treated, they actually get better?

Yup.

There’s even placebo surgery.  People with a knee problem were anesthetized, the surgeon made an incision, then just sewed it up without doing anything, and people got better!

So what do they mean by “just” the placebo effect?  This is amazing!  While many scientists sniff at the placebo effect, they clearly recognise that it exists, or they wouldn’t have designed the blind trial.

But just a minute here.  That’s why they designed the blind trial.  But what about the double blind trial?

Well, that’s because they also recognise that what the experimenter believes can also effect the outcome of the trial.  Hmm.  Weirder and weirder, don’t you think?  Obviously, of course, you can’t have double-blind knee surgery, but still …

So, we have our sweet-feet pill, and we design a double blind trial.  You’d think, if the pill worked, one group would have sweet feet and the other group smelly feet.  No: doesn’t work like that.  What we are looking for is for a “statistically significant” number of the sweet-feet group to see some improvement.  You never, ever get 100% cured with the real pill and 100% not cured with the placebo.

Never.

Here’s a fun one; some researchers wanted to test out the claims of some herbalists that the herb ginkgo biloba can help with sexual problems.  They found that it didn’t.  But they didn’t find that no-one got better, they found that equal numbers of people got better in both groups!

The aim of this study was to examine the effect of Ginkgo biloba on antidepressant-induced sexual dysfunction. The Ginkgo biloba (n=19) and the placebo groups (n=18) were divided; each to be administered with Ginkgo biloba and placebo respectively for 2 months by means of a randomized placebo-controlled, double-blind study. The results of this 2 month trial were: (1) there was no statistical significant difference from the placebo at weeks 2, 4 and 8 after medication; (2) in comparison with baseline, both the Ginkgo biloba group and the placebo group showed improvement in some part of the sexual function, which is suggestive of the importance of the placebo effect in assessing sexual function.

A placebo-controlled, double-blind trial of Ginkgo biloba for antidepressant-induced sexual dysfunction

Last point before I get to why I am telling you all of this.

Some people suddenly realised that, because all drug trials are done using double-blind trials with placebos, there was an awful lot of clinical trial data about placebos.  If you analyse it, you see that some people are “placebo responders”: pretty much they will get better whatever you give them, whether it’s the drug or a chalk pill.  And then there are the placebo non-responders.  They won’t get well whatever you give them.  I bet you are already thinking of a few grumpy people that you know for whom nothing ever works.  And a few Pollyanna types for whom everything is always wonderful.  If you’re a placebo-non-responder you probably spend your life wanting to slap some sense into the Pollyannas of this world.

If you find this stuff fascinating and want to know, this may be the place to start: What Is the Placebo Effect? By Kendra Cherry, About.com Guide.

Diets

Well, it’s taken me long enough to get to the point, but here it is.  I would be willing to bet that, for every diet, nutrition plan, weight-loss pill that’s ever been invented, however crazy, there is at least one person for whom it was a miracle cure and changed their life.

And for every serious, perfectly researched, based-on-pure-science-and-nutrition, life-style change that’s ever been invented, there are a whole host of people who got fat and sick and died a horrible death using it (well no, probably not that bad, but you get my point).

All of this is because, in my next post, I am going to try to create a map of the dieting, weight-loss, lifestyle territory, and I want you to understand that, while I may sneer at some things, and exalt others, I just know that there are people for whom the silver-bullet capsules filled with floor sweepings worked like a dream, and I’m sure that there are people who have eaten a Big Mac, fries and a full-fat Coke with extra sugar every day of their lives and went on to win Olympic Gold in the Ultra-Marathon.

But I’m also willing to bet that neither of those people are you!

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