Wednesday, 27 August 2014

Health, diet and the understanding of what science can do.

A good old fashioned English Breakfast
The Independent newspaper today has an article The science of saturated fat: A big fat surprise about nutrition? which seemed very relevant to me at the moment for family reasons.

Earlier this I was given a very robust talking to by the nurse at my doctor's surgery and as I result I have already lost 7 kg by reducing portion sizes, eating more fruit and vegetables, and cutting out between the meals nibbles. I am taking the need for a daily walk more seriously, and spend an hour a week in our local swimming pool. I am well on track to achieve  my target of 10 kg lost by Christmas, with further losses in the New Year. However my current eating habits may need further  modification when I hear the result of a blood test next week.

Over the bank holiday weekend I had planned several further posts on this blog but was distracted by a urgent phone call - as a close relative was rushed to hospital four days ago with a heart attack. Fortunately it was more of a sharp warning and after an angioplasty the signs are good - but he is even more overweight than I was and one of the matters he will have to address is his weight. We have already had some discussions about what the doctors might recommend.

And so to the newspaper article, its statement that saturated fats do not cause heart disease, and the discussion of why the earlier research was wrong. The article suggests that Our fear of saturated fats began in the 1950s when Ancel Keys, a pathologist at the University of Minnesota, first proposed that they raised cholesterol and therefore caused heart disease. It then goes on to review the findings of Ronald M Krauss when he reviewed the literature on the subject and was able to show that the evidence of a link is inconclusive. The story sounds plausible and he may be right.

The problem is knowing what one can believe. There must be many possible links, some strong, some weak, between the food we eat and our health and in theory science can look for and measure the effects. I know enough about science to know that in theory I could look into the literature in detail and assess the reliability of the information for myself. I could but I don't have the time or motivation to do so. I also realise the very real difficulties of carrying out long term dietary research over several decades in a way that will return statistically significant results. My father was, for a time, a tobacconist and can remember the years it took to get people to accept that smoking could damage your health.

However I have noted that the article is linked to a publication of a book, and there are many different books on the market, articles in magazines and on web sites, and programmes on television which give conflicting advice. Most would claim they are backed by science and a very significant number have commercial interests which could influence their objectivity. 

All this must influence what people think about science. Every one has to eat to live and is interested, in the short term at least, in their health. Good science has difficulties in providing reliable predictions about long term effects of diet - and there is much pseudo-science, such as homeopathy, which has no scientific foundations. This gives Joe Public the impression that science is unreliable, and the lack of understanding could well encourage people to take up issues which have no sound basis. 


  1. Just a thought, I appreciate you may not want to review the literature, there may however be a shortcut, i notice you appear to have an interest in anthropology,if you examine what our ancestors were likely to have evolved to eat this may give you clues to what might be healthy to eat, there is a name for this way of eating, they call it the paleo diet.

  2. tcthink - if you understood anthropology you would realise that man evolved to make the best use of whatever food sources were available in the area where they lived - be it fruit, tubers, shell fish, birds eggs or red meat - and even then they would often gone hungry and died comparatively young. Man evolved to eat anything that was available - and as much as possible - because there was a danger of foodless days. In addition he lived a far more active life which also kept him fit. Modern man follows the evolutionary pathway to eat as much as you can when it is available - but now the supply of food is effectively unlimited - with no periods of starvation - and not enough exercise to burn off the surplus energy.

    A real paleo diet would be to only eat wild food that you collected yourself within five miles of where you live - which means people who lived in different parts of the world would eat very different diets. As mammoth bones have been found close to where I live a healthy paleo diet for me would include large portions of mammoth steak. Sounds delicious - perhaps I could eat beef rather than starve if my mammoth hunt proves unsuccessful.

    As far I can see Robb Wolf's book "The Paleo Diet" is just one more example of an author's attempt to earn money by giving a different posh name to eating sensibly and making it look more respectable by padding it out with a lot of pseudoscience. The dietary recommendations in his book will be very much better than starting every day with a full English Breakfast, a generous business lunch entertaining clients, and a slap up meal in the evening.