Correlation is not causation

It is the Christmas holidays in New Zealand and in the Southern Hemisphere we are all in t-shirts and at the beach for the most part. Business in New Zealand closes down for most of January and is pretty sleepy in February as well on account of the summer music festivals and summer days.

Over the break a New Years resolution story caught my eye. Two old people ran around Australia in 2013 in the process covered the equivalent of 365 marathons in one year. The headline Couple run 365 marathons in a year is a bit misleading as they took up to 9 hours each day to do their “running”. To put that in context a world record for a marathon race is just over 2hrs – see marathon world record times A marathon distance is 42.195 kilometres.

The first thing I noticed about the Aussie story is that that the runners are taking a long time to cover the 42km and that they are are aged 64 and 68. Good on them for getting off the couch to do the runs; but here is where it gets a bit confusing ( and misleading) for me.

The Australian story makes a big deal of the fact that the two runners are vegans and part of their objective was to prove that being a vegan and running that distance was very achievable and so on.

When I mentioned this story to a friend they thought it was a hoax on account of the runners both being in their 60’s. The vegan diet was thought to be not so interesting and not that relevant but to the runners – they felt they had proved their diet was a good one.

The real problem with a story like this is to find a comparison. After all how often do you hear about about old people running that many marathon distances?

It turns out that running a marathon in old age is not so unusual.

In fact Fauja Singh ran “5 hours 40 minutes at the age of 92, at the 2003 Toronto Waterfront Marathon“. He was still running at the age of 102 last year in a marathon in Hong Kong. Fauja is a vegetarian but that is for religious reasons rather than for diet.

In 2010 Stefaan Engels ran 365 marathons in one year at an average of 4hrs for each distance. His fastest time was 2hrs and 56 minutes and that is very respectable. His times were much faster that the Aussie couple but then he was a relatively youthful 49 at the time.

Engels attributed his success to the fact that he ran slow times for most of the marathon distances.By contrast the Aussie couple ran almost twice as slowly for their recent year long run. The Aussie times were not much faster than walking when looked at more closely. There is a huge difference in impact between walking 42 km per day and running that distance in 3 or 4 hrs.

For energy, he feasted on pasta – or paella when in Spain – meat, fish and a little wine. “At first the doctors said you have to take vitamin supplements and follow a certain diet, but I just ate whatever I wanted,” he told The Independent. He also slept up to 12 hours a night; his sole medicine: a daily aspirin.

Akinori Kusuda is another marathon runner who has run more than 50 marathons. Back in 2009 the 65 year old ran 52 marathon distances in 52 days culminating in the Tokyo Marathon of that year. Not sure what Kusuda ate but I would assume it was Japanese food with maybe extra carbs in the form of rice. The point is – his diet is not mentioned as a factor in his success (although it may well have been one.)

I did see a newspaper story where someone mentioned that Forrest Gump ran for 3 years. I hope they were joking as Gump was a fictitious character but there was no sign that they appreciated that fact.

I’m interested in the story of the two Aussie runners doing the 366 marathon distances because it suggests that they could do that distance because they were vegans and then uses that to promote the vegan lifestyle.

Correlation is not causation. Just because their diet was vegan doesn’t actually prove that they couldn’t have eaten something else and done the same same distance.

Indeed Stefaan Engels proved that you could eat almost anything. However he did have a high carb diet and there are very good reasons for this. As it happens eating 10 banana’s for breakfast and up to another 10 during the day is a great way to add carbs and plenty of endurance athletes and cyclists do this but not because they are vegans.

In “Mathematical model helps marathoners pace themselves to a strong finish” mention is made of a formula for marathon runners who want to calculate the amount of carbs they need to run.

The Endurance Calculator is designed to enable endurance runners to determine safe, personalised racing paces over distances such as the marathon.

For anyone running or exercising over long distances. Cyclists do this a lot – carbo loading is well known. That includes pasta and banana’s which are both high in carbs.

Where I have a problem with the Aussie marathon running story is the idea that because those two could run 365 marathon distances in a year then being a vegan is a good idea for the rest of us.

That is just wrong and most of the problem is that way that we do a “fast thinking” link and connect the extreme running and the vegan diet and the slow thinking answer is that plenty of people run marathons including very old people. What is also distressing is that in none of the media reports does any journalist question the idea at all.

We want to spot a pattern or linkage between the diet and the ultra distance and it is not really there except that carbo loading was a good idea for walking / running long distances.

If they want to run well they all carbo load but most of them are not vegans. For a more detailed nutritional analysis of eating lots of bananas see 30 bananas a day. The Aussie runners claimed to eat up to 20 banana’s per day and would have similar challenges but it did not make them super athletes or prove anything about the vegan diet.