Caster Semenya

First things first, Caster Semenya is a wonderful athlete who won the Olympics fair and square. The whinging and bleating from those behind her is disrespectful at best and downright racist at worst. Those athletes who didn't finish on the podium should keep their mouths closed and go back and do some more training.


This doesn't get over the thorny issue of how we should separate groups that compete in sport. We find it easy to separate by weight as the measurement is very objective so no one complains. But what about dividing by sex? If we are going to have categories then its important that way of categorising people is both fair and transparent. It seems to me that there are a couple of options-


Option 1 is to leave things as they currently stand which seems to be to allow anyone self-identifying as female who doesn't have a penis to compete in the female category (although I'm not aware of any official and transparent penis checking). It's fine to go with this option but if you subscribe to it you must consider that at the next Olympics there might be 3 rich white American women with hyperandrogenism who beat 3 poor black African women without hyperandrogenism who got to the final against all the odds through hard work and dedication. If you are prepared for that to happen then stick with option 1.


Option 2 is to divide people by testosterone level and basically have categories of 'testosterone <10 and no penis' and 'everyone else'. This is basically how the rule stood for the London Olympics and you must remember that Caster basically won that race. She was only beaten by a serial drug cheat. If you go for that option where would that leave Caster? She would have the option of taking medication to lower her testosterone (she would probably still win) or competing in the 'everyone else' category where she would undoubtedly lose. Difficult for her and other athletes with hyperandrogenism I'm sure.   


Option 3 is to come up with some other (as yet undefined) way of dividing athletes which is fair and transparent. It's hard to know what that could be but there might be some options.


Option 4 is radical and likely to be unpopular. Have a third category. Have a race for 'testosterone <10 and no penis', another for 'has a penis' and a third race for 'everyone else who doesn't fit in the other categories'. Perhaps the third category should run in the Paralympics? Intrinsically people won't like this, they won't enjoy the thought of Caster running in the Paralympics as if she's 'disabled'. Anyway I'm just putting it out there as an option.


Berating the athletes who missed the podium and lashed out at Caster and co is all well and good- in fact I applaud it but you must be aware that you need to pick an option from the list above and accept the consequences. That is unless you can think of a better plan.

Banters and statins

Being a Banter is a bit like being a member of the American political group the Tea party. The similarity is that if you join the group you’re obliged to follow all of the beliefs rather than simply the ones you actually, well believe in. Tea party member believe in small government and deregulation of markets, they are also vehemently against President Obama and just about everything he says. These political views are bedfellows, but what is strange is that Tea party members also all seem to believe that climate change is not man made. This is interesting because it’s a scientific rather than a political point and so it would be perfectly rational to believe in the political parts of the doctrine but to disagree on the scientific. Tea party members however almost never do.

Banters are similar to this as I’ve pointed out previously. They have at least 3 points that they all believe in, firstly that LCHF diets are optimal for human health, secondly that sugar is both toxic and addictive and thirdly that statins are bad for you. These are all scientific points and it would be reasonable to accept one or two of them without the others but just like Tea party member, Banters seem to see it as an all or nothing.

You don’t have to look far to find Banters going on about the lack of benefit and the frank dangers of statins. Christine Cronou who definitely ranks as part of the lunatic fringe likes to write about the dangers of statins, recently warning us about 20,000 people with side-effects and 220 deaths in the UK alone. The source of these data were none other than the Daily Express, which is hardly a bastion of good science. Zoe Harcombe may not quite be on the lunatic fringe but she is definitely a self-publicist determined to make money out of LCHF regardless of the science. She is constantly telling us about the dangers of statins and has written such priceless pieces as ‘How statin drugs really lower cholesterol & kill you one cell at a time’. 

So what is the evidence behind statins? Doctors tend think of two distinct groups of patients when considering statins. There are those who have had a heart attack or stroke and prescribing for them is called secondary prevention; to prevent a second event if you like. Alternatively there is primary prevention which is prescribing statins to prevent a first ever heart attack or stroke. The evidence for secondary prevention with is overwhelming. They clearly have a beneficial effects and the evidence is so strong that even some Banters are persuaded. The size of the effect is not large however, whatever statins are, they certainly aren’t wonder drugs. For someone who’s had a stroke and has a 25% chance of having another one in 5 years a statin will reduce that risk to 20%. This is a modest effect but one that many patients would welcome.

Debate on primary prevention is far more intense. In fact, there is clear evidence of benefit of statins for primary prevention, the problem is that once again the effects are modest to say the least. A recent review looked at the data from 27 randomised trials and concluded that on average statins reduced the relative risk of major coronary events by 24% for each 1 mmol/L reduction in LDL cholesterol. This means that it was reduced by a quarter from its original level e.g. reducing from 4% to 3% risk. The effect on stroke was a little less but still 15%. Benefits were similar between women and men, smokers and non-smokers, in elderly and young people, and across all levels of obesity, blood pressure, and glucose. A 24% relative risk reduction means different things to different people but is usually little more than a 1% drop in absolute risk. This would mean that only 1 out of every 100 people on a statin would get a benefit. 

The Banters love to gloss over these modest effects but even more so to focus on side-effects of statins. There are of course side-effects, all beneficial drugs have them but once again it’s a question of degree. Most side-effects are mild and if patients experience them they can simply stop the drug and the effects go away. Very rarely side-effects can be life threatening but this is so rare as to be outweighed by even the modest beneficial effects.

So once again we find that the Banters argument isn’t backed up by the data, but neither in my opinion is view that statins are wonder drugs. As usual the reality lies somewhere in between and isn’t sensational enough to sell newspapers or books. Statins work, but the effects are modest. They have side-effects which are usually mild and go away if you stop the drug. Hardly enough for a best seller.

Banters and the first law of thermodynamics #LCHF

Banters (followers of the Banting diet) have an interesting relationship with the first law of thermodynamics. They seem to both love it and hate it at the same time; using it to both enrich their own arguments and to dispel their opponents. In reality there is no reason to fear the law as it is perfectly compatible with the Banters views, however their uneasiness gives away many underlying insecurities.

The law states that energy can neither be created nor destroyed so that within a closed system a change in energy equals what you put in minus what you remove.

Change in energy = Energy in – energy out

When it comes to body weight this means that if you put more energy in than you take out you accumulates energy and gain weight. I’ve heard Banting heavyweights such as Gary Taubes and Dr Stephen Phinney discuss this issue and they seem threatened by the equation as if non-Banters are saying   ‘it doesn’t matter what you eat, when it comes to obesity it’s simply a matter of energy in and energy out’. Banters, of course, see this as a threat because they believe that you have to eat LCHF to lose weight and it very much does matter what you eat.

One of their arguments is that if body weight were simply energy in and energy out anyone eating just one extra spoonful of food per day would gain mountains of weight over a decade. In reality, many people maintain a fairly constant weight over long periods of time. They never go as far as to say the equation must be wrong but rather that there is some issue with its direction. They claim that non-Banters are wrong in saying that energy in minus energy out leads to change in energy (weight). Instead it is change in weight that leads to energy in minus energy out. I have never seen any evidence presented to back this up but and how could there be when there is no arrow in the equation! The simple fact is that there isn’t an arrow in the first law of thermodynamics any more than there is one in E=MC². Equals signs just don’t have a direction. It isn’t a case of one thing leading to another it is a case of each side of the equation being equal.

While Banters tie themselves up in knots with this argument they miss the obvious which is that the theoretical non-Banter argument is false but in a different place. It’s the first half “it doesn’t matter what you eat” that is wrong while the second part “it’s simply a matter of energy in and energy out” is correct. Of course the second part is correct; it’s simply stating the law that no one disagrees with. I’m not entirely sure why Banters miss this point so regularly but I think it’s because they embrace simplicity rather than complexity. The simple fact is that body weight homeostasis is an incredibly complex issue not easily summed up in sound bites and one liners.

Other that a few very minor factors we take in all our energy through our mouths by eating and there are a multitude of factors controlling how much energy passes our lips. These include, but are not restricted to, availability of food (you can’t eat if there is no food available), mental health and emotion (depressed people tend to eat less, those with Seasonal Affective Disorder SAD eat more), income, appetite and satiety, drugs (many psychoactive drugs cause increased appetite). Many of these factors are inter-related and are never the same for 2 separate people. 

While factors controlling energy in are complex that is nothing compared to energy out. Factors include environmental temperature, basal metabolic rate, the thickness of our clothing, thyroid status, amount of exercise, the make-up of the gut microbiome, amount of sleep, any illnesses we have (e.g. cancer) and many other environmental, genetic and epigenetic factors that are not well understood.

It’s a pretty amazing fact that many people have a very stable weight over many years when a tiny tip in the energy balance each day would be enough to see large changes in weight over time. Clearly there is some very fine tuning in the way the body regulates weight particularly given the number of variables involved. I don’t pretend to fully understand this process but what I think the Banters should learn is to embrace the complexity of the situation, pay attention to the facts and stop worrying about the first law of thermodynamics.

What's right with the Banting argument? (but hardly original)

I began this blog with discussion of what is wrong with the Banting argument; while there is more to come on that subject I would like to turn my attention to what is right with it.

One thing I think anyone interested in nutrition can agree on is that there is a problem. Certainly in South Africa there is overwhelming evidence of very high levels of obesity which directly correlate with poor health outcomes. In a recent high quality article it was found that in 2013 the rate of obesity in South African women was 42%. This compares to a rate of 34% in USA and although South African men do better it's a shocking statistic. The map below summarises adult female obesity across the world with South Africa being one of a handful of countries in the red zone.

 

 

I have heard Professor Noakes on a number of occasions say that people in South Africa are obese because they don't eat a LCHF diet. He is somehow implying that if you disagree with the LCHF argument you must also think there isn't a problem. This couldn't be further from the truth. Whatever anyone thinks about dietary strategies, no one in their right mind is denying that there's a problem.

The Banting argument has at least 3 tracks which all followers seem to agree on. First it is that LCHF diets are the equivalent of 'the elixir of youth', secondly that sugar is very bad for you and thirdly that statins are pretty much the work of the devil. Whilst points 1 and 3 will be the subject of future posts there is a great deal of evidence showing the harms of sugar. If you only read one academic paper about sugar its worth reading Sanjay Basu's The Relationship of Sugar to Population-Level Diabetes Prevalence: An Econometric Analysis of Repeated Cross- Sectional Data. The data in this paper are purely observational and therefore sit very low in the EBM pyramid. However, this group make a convincing argument for the role of sugar consumption in diabetes. There is unlikely every to be a randomised controlled trial of a high sugar diet and so this is the highest level of evidence we are ever likely to get on this precise question.

Karen Thomson is part of the LCHF community and is very vocal on the dangers of sugar. Her website and books are titled 'The Sugar Free Revolution'. Whatever the truth of the message one thing Karen Thompson is not delivering is a revolution. In fact her story is rather old hat. If you only read one book on the subject I recommend 'Pure White and Deadly' by John Yudkin.  Yudkin was a pioneering endocrinologist who cottoned on to the dangers of sugar way back in the early 1970's and wasn't afraid to tell the world. The problem was that the world wasn't ready to listen. Gradually however the world has woken up to the dangers of over consumption of sugar. There is no reason to think you should be completely sugar free any more than you should be completely alcohol free but consumption in moderate to high quantities seems to be dangerous.

So, its easy to agree with the LCHF brigade on a number of issues. Firstly that there is a big problem with diets in South Africa and secondly that sugar in large amounts is probably dangerous. Neither of these is revolutionary or novel but that doesn't stop people writing books and making money out of them.

References

Ng et al Global, regional, and national prevalence of overweight and obesity in children and adults during 1980–2013: a systematic analysis for the Global Burden of Disease Study 2013. Lancet Volume 384, No. 9945, p766–781, 30 August 2014 http://www.thelancet.com/journals/lancet/article/PIIS0140-6736(14)60460-8/fulltext

Basu S, Yoffe P, Hills N, Lustig RH (2013) The Relationship of Sugar to Population-Level Diabetes Prevalence: An Econometric Analysis of Repeated Cross- Sectional Data. PLoS ONE 8(2): e57873. doi:10.1371/journal.pone.0057873