There are two main things that have caused us to get it so wrong when it comes to human nutrition.
Firstly, it's really bloody hard to conduct good experiments in this realm. Money, practicalities and ethics make it neigh-on impossible to conduct anything more than short term experiments in limited participants. It's hard / inappropriate to extrapolate results over longer term, or to different contexts such as race/ancestral history, different dietary habits, age, lifestyle and health state.
Secondly, bias and funding have huge influence on the research that can be done. Sometimes intentionally, sometimes not. If all the funding is coming from the sugar industry, what are the chances that fats will be demonised? If the drug companies think a study will show there is a simple dietary fix to the problem solved by their leading drug, do you think they will throw their money and support behind it? If you're results are different to what 95% of your profession are saying, are they going to turn against you if you start telling them all they are wrong?
The other point is the trouble with old media. Before the social media age, we were at the mercy of the gatekeepers. The mainstream media controlled the messages we would hear. The mainstream media are heavily influenced by their sources.
So, we have been left with only bad epidemiology, 'expert opinion' which is based on very little real science and the messages we've been allowed to hear.
As a result of this, we have been left with all this bad advice, which has been reflected by the poor health of our society.
Fortunately, things are improving with time. It's now impossible for disingenious scientists to publish they're manufactured findings through the only media outlet available and push their agenda without challenge.
The data they used has to be available to anybody who wants to look at their methodology and analyse the data for themselves, and thanks to social media, there are now many more avenues to get that information out to the public.
While the masses with no real interest in nutrition may well still receive only the official party line through the mainstream outlets, sponsored by those with agendas and huge budgets, at least those of us who wish to show an interest can learn where the science comes from, the various arguments for and against certain theories and stand a much better chance of making choices that help us get healthy.
No longer do we simply have to accept the government guidelines and sensationalist newspaper theories as fact. Now it's much easier to consider the source of the information, the context and the biases involved.
Next time you see a sensationalist headline that reads "Meat causes colon cancer", I hope you'll think to ask "is it an epidemiological study", and then ask, what about if eating less meat causes us to eat more sugar, isn't that the primary cause of cancer from food? Why is that not getting any press? What about other diseases? Why is this not presented in context? Is the relative risk above 2.0 or is the newspaper taking a study which is failing to show any significant corellation presenting it as fact? Why are you promoting an experts opinion without disclosing their biases?
Because only then, are you equipped to decide if you should take any notice of the silly headline.
Nutrition science is terrible and heavily influenced. Keep your guard up.
Now let’s get to the important stuff...