Often we see articles published in magazines with blazing titles telling us how science shows that we need to avoid certain foods or eat certain things. But we then read the complete opposite advice the week after! In sports science we have seen some great examples recently.
For example, we have seen headlines for ice baths. One day they are recommended the next day you need to avoid them! Or we see headlines for sugar, one day sugar seems bad (even toxic!) and the next day it is good. Or we are recommended to train with carbohydrate or without carbohydrate! Antioxidants are good and the next week bad!
How is this possible? Why are all these scientific studies contradicting each other?
In this articles I am trying to get to the bottom of this issue. Before we discuss this, we need to understand a little more about what science is and how it works. What is science?
One of the best and easiest to understand definitions that I have come across is this one by Astrophysicist Neil deGrasse Tyson:
“Do whatever it takes to avoid fooling yourself into thinking something is true that is not, or that something is not true that is”.
Science refers to a method where you make observations, and formulate a hypothesis about the truth. You then carefully design a study to test the hypothesis, and your data will either support the hypothesis or not. If it doesn’t, scientists admit that they may have been wrong and adjust their hypothesis and test the new hypothesis. Science distinguishes itself from all other branches of human pursuit (like religion) by its power to probe and understand the behaviour of nature on a level that allows us to predict with accuracy the outcomes of events in the natural world (1).
The outcomes of scientific studies will depend on many factors. In sport science for example, the outcomes will depend on the way the research is conducted (study design), the level of the athlete (world class or recreational), trained or untrained, the environmental conditions, the diet, the time of day of the measurement and many other factors. When two studies are compared, some of these factors are going to be different, so you are hardly ever comparing like for like. Conclusions of a study are therefore often highly specific to the conditions of the study. We then try to extrapolate these results to a wider population, but have to be very careful when we do this. For example, if we find something in a test tube, it does not mean the same thing also works in a living human. If we find something in a patients with a particular disease, it does not mean that we can extrapolate these results to elite endurance athletes! The conclusions of a good study will take this into account and be specific to the conditions.
It is usually not the studies that contradict each other, but the interpretation of the results! Popular press usually doesn’t have the patience to try and understand all these factors that could have influenced the results. And the conclusions directly from the scientific paper are not “reader friendly”: if it specifies too much that this is only found in these patients with a particular disease. It makes a much better headline to immediately extrapolate this to the elite endurance athlete and people will be reading the article!
This of course is a disservice to the reader as well as to the scientific process. Although we need to translate science into practical recommendations (and I have tried to do this my entire career), when we do this, we should never do it on the basis of just one study. We should look at all the studies, understand the “totality of evidence”, understand the shortcomings of certain studies and then make a decision on what the best advice would be. When we give the advice we still need to be specific who the advice is for!
For example, creatine may be a supplement that works, but it will work in very specific condition for individuals with very specific goals. But for other athletes, with different goals and in different conditions the results of creatine supplementation may actually be negative! We refer to this as the context, and usually advice without the context is poor or counterproductive!
So when reading articles, always be wary of conclusion based on one particular study. Ask yourself what other evidence is there to support, compliment or contradict this particular study. If an article tries to draw conclusions far beyond the study, that is very likely a problem. What you really want to know is: what does the totality of evidence tell us and how much can we really extrapolate the results?
Over time, science discovers objective truths. These are not established by someone who is seen as an authority, nor by any single research paper, no by anecdotes. The popular press, in an effort to break a story, may mislead the public’s awareness of how science works by headlining a just-published scientific paper as “the truth,” (1).