By Dr John Orchard, @DrJohnOrchard

Dr J, takes a look at the hottest diet in the world right now.

Just for a change, this Dr J column is written about a topic which I am not an expert on. Why change a good formula? (In fact you can take it as a very good rule of thumb that articles published under my real name in Sport Health are ones on subjects I profess to have expertise in and expect to be taken entirely seriously, with the converse often applying to Dr J).

With that said, last year there were some Dr J articles on concussion and drugs in sport, which need to be considered as serious topics (but for which there are specialists that know more on the topic than I do).

Nutrition is a science that you can gain tertiary qualifications in, which I do not have. However, everyone likes to think that they know the ‘basics’ on diet. We all think we can pick a better Test team than the (expert) Australian selectors, run policy better than the (expert) Prime Minister, know more about which stocks to invest in than (expert) fund managers and have a better chance of selecting the winner of the Melbourne Cup than (expert) bookmakers.

Given we all cook and eat food, there is also a tendency for all of us non-dieticians to think that we know more about nutrition than the experts do.

Actually on this point I’d like to digress to an important observation on football clubs. The one job that everyone at a football club secretly thinks that they could do better than the incumbent is the head coach job (as evidenced by softly spoken comments of “I can’t believe he picked him/subbed him/played him in that position” being heard wherever you travel within the club).

However if anyone happens to verbalise any of these suggestions directly to the head coach then it is almost an automatic sackable offence. In contrast, the majority of the other positions in a football club are appreciated as being of a specialist nature which can only be filled by someone with the appropriate qualifications.

Despite this, the head coach has the authority to tell anyone in their alternate specialist position what to do in their job without sanction (e.g. tell the recruiting manager who to recruit, tell the doctor when a player is ready to come back from injury or tell the marketing manager who will and who won’t be speaking to the media, tell the psychologist which player needs time off for counselling and which player is OK to keep playing & tell the CEO which player needs to be sacked for bad behaviour and which one needs to be retained).

The head coach can also sack any other member of the staff, but in return for this power ultimately will be more likely to get sacked himself. End of digression, but the point hopefully made that we all love to claim expertise in areas other than those in which we are trained.

So now that we’ve established that sport and nutrition are two subjects we are all amateur experts, that gives me the right to pen an article on the Paleo diet as an amateur expert, just as you’ve got the right – as an amateur expert or real expert reading it – to reject whatever I have said about it because you know better.

The Low Carb High Fat (LCHF) diet has existed in a number of different incarnations over the years, which raises the question why am I writing about the Paleo diet rather than the much more descriptive LCHF diet, or the Atkins diet?  The answer is that the Paleo diet is the current trendy label, and when I refer to it I’m speaking about it as a concept encompassing its promotion as well as the LCHF recommendations.

Once you’ve looked at the concepts within the Paleo diet you may decide that you sit in the camp that firmly disagrees with everything about the Paleo diet. That’s fine and really is up to you, but what you’ll struggle to disagree with is that it has achieved “breakthrough” status.

People are talking about it, the mass media is writing about it, people are tweeting about it and it’s all over Facebook.

Perhaps those in the nutrition fields will be able to tell me that fad diets come and go every couple of years and sell many books, but the rise of social media in recent years means that whatever the diet of the moment is, it generates far greater penetration into the public consciousness than similar incarnations in previous cycles of the concept.

We have recognised that applied science as a field shouldn’t divorce itself from the real world. It is one thing to scientifically prove, for example, that smoking is bad for you, but another separate challenge to get people to stop. Pure scientific facts don’t tend to move people to act on things like diet, but trendy concepts can create action.

It is a great question to sit back and consider why the “basics” of good nutrition are considered passé or boring by the mass media, but the Paleo diet (which as mentioned is a rehash of earlier diets) is suddenly highly newsworthy. It has everyone talking about diet and what is healthy and what is not. The value of this traction is not to be underestimated.

Hakan Alfredson didn’t invent eccentric exercises for the Achilles tendon, but presented them in a way that gave the idea traction and got it going as a popular concept. Although they are merely early converts to low carb – high fat, megastars of the sports medicine world like Tim Noakes & Peter Brukner are ensuring that almost everyone in the sports science and medicine world knows about this diet and many people are disciples of it.

So what has the evidently popular Paleo diet got going for it?

By far its biggest strength is in the myth buster category. One of the myths it busts is the low fat con job the food industry has been pedalling for a number of years. To market products as healthy on the basis of being “low fat” (or worse “low cholesterol”) has left many people utterly confused as to what is healthy and what is not. In these foods you’ll find that the low fat version has simply substituted the fat for sugar.

Given that once it’s in the body sugar can convert easily to fat, at best it is misleading to promote a “lower fat higher sugar” variety of a product as a healthy alternative. At worst, this misinformation means that, at least for some people, they will put on more weight when they choose the low fat variety over the full fat. This is because sugar is less filling than fat and there may be a greater likelihood of overeating.

Whilst I would like to think that personally I have never fallen for this three card trick, there is no doubt there were probably food categories in the recent past (e.g. yoghurt) where out of reflex I have  purchased the “low fat” variety, considering it a “healthier” choice, when the truth is I have most likely exercised poor judgement.

The fact that Paleo rejects this demonization of all fats means it gets a tick in the plus column from me.

The second myth buster concept associated with the wider promotion of the Paleo diet has been the exposing of the pharmaceutical industry as an on overly zealous promotion of statins. I’ll resume a defence of the correct place of statins in a minute, but I am certainly sold on the concept that the drug companies who make statins (and their non-independent experts) have allowed science to be corrupted by sales.

On the basis of seemingly poor or compromised scientific evidence, there have been recommendations made that individuals with low risk of heart disease be prescribed statins, or even the entire population over a certain age.

From what I have read that appears to be scientific, statins do seem to significantly lower risk of dying from cardiovascular disease (CVD) but in return increase risk of dying from other diseases.

Therefore whether they are a useful drug worth taking depends on whether an individual is particularly at risk of dying from cardiovascular disease or not. The sensible middle ground seems to consider that calls for low CVD-risk people to be force-fed statins in the water supply are erroneous and outrageous.  On the other hand it is equally outrageous to suggest that no one should take statins, as those at the high CVD end of the spectrum appear to conclusively reduce their risk of mortality if they take them.

It is at this point that following the Paleo trend to the cult end of the spectrum becomes very dangerous. The hypothesis that a high fat low carb diet across the board is a healthier way of lowering CVD risk than statins is – at best – an unproven hypothesis and possibly has already proven as false.

However you can’t get into debates on this topic without getting dragged down into specifics of what each individual Paleo disciple believes. Of course, if you substitute sugar (a carb) for olive oil (a fat) you are probably going to get generally healthier outcomes.

If on the other hand you substitute brown rice (a carb) for something containing trans fats (a fat) then you are probably going to get generally less healthy outcomes.

You can go around and around in circles with examples and counter-examples along these lines. If an individual wants to swear that they have turned their life around by “going Paleo” and by this they mean reducing their intake of processed carbs, drinking less alcohol, exercising more, sleeping regular hours and giving up social drugs, then I will take my hat off them for turning their life around but would also point out that there is nothing that they have done that a mainstream (non-Paleo) nutritionist wouldn’t have recommended to them in a consult.

When it comes to the scientific evidence that assesses a more formal comparison of low carb diet versus low fat diet, from what I have read (as a non-expert) there does appear to be substantial RCT evidence that carb restriction is better than fat restriction for getting weight loss in an overweight population.

The likely mechanism/explanation for this is that overweight people often struggle to control portion size and this appears to be easier to do on a high fat low carb diet than the reverse.

So if this is your status (overweight) and your desired end point (weight loss) then there appears to be good scientific evidence in support of the Paleo approach. However does this translate into LCHF being a ‘healthier’ diet for those people of normal body weight? Not that I have yet seen.

The fact that enormous Asian populations have a diet based on a major carb (rice) and low rates of obesity suggest that LCHF is not a universal human requirement for weight control (even though it might be effective for many individuals).

And does it translate to lower mortality for those on a LCHF diet? Again not that I have seen. Many of the Paleo disciples are quick to criticise statins on the basis that they “only lower total cholesterol” and that this does not necessarily translate into lower mortality.

However I haven’t yet seen the evidence that LCHF leads to greater longevity than other healthy diet options.

Yes, it is intuitive that weight loss would lead to lower mortality but it isn’t a given. It was intuitive that low fat diets would lead to people becoming less fat, but the Paleo people will swear that this is not true, so something intuitive should not be accepted without adequate study.

It certainly is hard to prove a link between diet and mortality, yet it is well established, for example, that high red meat intake is associated with higher risk of dying from bowel cancer. Lowering intake of red meat would be one of the first things you might do if your end point is living longer, but it is something that many Paleo experts will insist you can increase as it is low carb. It is a further example – according to me – that diet is complicated and it is unlikely a simple “rule” is a cure-all for future medical problems.

My current belief is that there is almost certainly no simple mantra by which you can define the “healthy” diet for all people. Yes, if you have Coeliac disease or are gluten intolerant then avoiding carbs based on wheat is going to make you healthier and a diet that resembles the Paleo one is going to be the best one for you based on medical indication.

The concept that all carbs are bad for everyone just doesn’t wash with me in light of what I read to date. If you narrow the attack to sugar specifically or sugary drinks like soft-drinks then maybe a low-sugar diet makes a lot of sense in general. But this is certainly not where Paleo ends, as traditional nutrition is also anti-sugar. The battleground between mainstream nutrition and the hard-line Paleo advocates is over pasta, rice, fresh fruit and bread, and again I have not seen any solid evidence to suggest that they are universally bad for all people. I accept that for overweight people trying to lose weight, and then these are potentially danger items that can lead to overeating. But they can also be included in a healthy diet such as the Mediterranean diet which seems to have an ‘evidence-base’ (cohort plus some RCT) as being associated with good health.  Pasta, bread and fruit (anti-Paleo) are staples in the Mediterranean diets (along with olive oil, fish, vegetables, nuts, yoghurt and wine which are Paleo staples). There are plenty of Greek and Italian people with unhealthy eating habits, but there does seem to be some evidence that their traditional diet is very healthy. That is, to the extent that these things can be measured. Diet is complicated and I appreciate it is hard to categorise an individual’s diet as healthy or unhealthy when it may be made up of, say, 32% healthy choices, 24% unhealthy choices and the remainder of uncertain status.

The lack of evidence of particular diets as being universally superior to others means that Paleo risks falling into the category of ‘fad’ based on anecdotal evidence. Just as one major snowfall in the US doesn’t disprove global warming, a retweet of someone who went on the Paleo diet and lost 15kgs doesn’t prove that high fat is better than high carb for all people. Social media may be responsible for the greatest triumphs of the Paleo movement (e.g. calling out the low fat / high sugar and other myths) but it also means that scientific proof can be glossed over (e.g. show me an RCT or even cohort study where Paleo knocks off Mediterranean diet for long-term health outcomes)

Another major component I strongly believe that all of the great diets of the world have is a love of food, specifically unprocessed food. Healthy eating habits are generally based on liking food rather than seeing a huge percentage of available food being something terrible that you have to avoid.

Yes, maybe we can all agree on heavily processed food (‘junk’) as being bad for you. The concept that all fats are bad for you (successfully debunked by Paleo) is only as silly as the concept that all carbohydrates are bad for you (promoted by Paleo). Many foods (including alcohol, meat and maybe dairy and pasta) appear to be very healthy in moderation and very bad in excess.

Some foods (fish and most vegetables) appear to be healthy in any quantities. Although there are exceptions to any rule you write – if you live near a polluted sea (Venice) and the fish contains toxins then maybe it is unhealthy to eat it too much, even though fish is generally a healthy meat.

It is complex and a matter of finding both balance and specific individual advice, with the healthy diet unlikely to ever be able to be reduced into one or two dot points. Which is a good reason why we have experts in nutrition and you need to study for many years to be fully qualified.

Exercise, on the other hand, is a no brainer. Regular exercise = good and no regular exercise = bad. It is only when you reach extreme levels of exercise (professional level contact sport, extreme sports) that you can question whether a negative/positive balance threshold has been crossed.

With exercise it is mainly about implementation (getting people active) rather than knowing what is good for you (almost all activity in moderation). It is also worth remembering that the evidence appears to suggest that exercise is the factor far more associated with superior health outcomes than diet which – to be fair – is associated more with normal (or abnormal) body weight than exercise is. If you want to have medium body weight, you need to focus on diet. If you want to be healthier (i.e. live longer) your diet has far less of a role than whether or not you exercise regularly.

So please look at Paleo and what it represents and try to take some positive learning points from it (that substituting fat for sugar is not a healthy trade-off) rather than an assumption that a simple concept (that carbs are bad for you) has cracked a diet code for everyone to successfully live by. If the Paleo concept is the trigger for you to take a healthy diet seriously and generally live in a much healthier fashion across the board (including exercising, being a non-smoker and using alcohol in moderation) than you would have otherwise, then by all means there is a lot in it for you. If it is an excuse for you to eat a lot of high fat food and think that this is the single magic bullet to good future health (neglecting exercise and being a non-smoker which are the closest things to real magic bullets), then it is potentially a dangerous fad.

*********************************************************

This article was also published in Sport Health Magazine. Sport Health is Sport Medicine Australia’s quarterly member magazine. The publication covers topical issues and the interests and activities of the various disciplines which make up the sports science and medicine community within Australia. Link: http://sma.org.au/publications-media/sport-health/

Dr. John Orchard is an Australian sports physician, injury prevention researcher, Cricket NSW doctor, and Associate Editor of BJSM

This blog is co-publication with Sport Health http://sma.org.au/publications-media/sport-health/