Schrödinger’s Fat – Confusion and Contradictions in Dietary Advice

Dr Sean Wheatley, MSc, PhD. Science and Research Lead
As anyone who works in, or has had any involvement with, the world of nutrition knows – no one ever agrees on anything.
Okay, that might be a slight exaggeration, but it is true to say that despite decades of research, and billions of pounds in funding, there are still huge areas of contention when it comes to what people should eat. This is never truer than when it comes to the roles of macronutrients – i.e., fat, carbohydrate and protein – with some quarters claiming fats/carbs/proteins (delete as applicable) will kill you, and others claiming fats (or carbs, or protein) have magical healing properties.
This is frustrating for everyone, particularly members of the public who want clear and practical advice to help them make changes that will allow them meet their personal goals.
Although I can’t clear up all the confusion here, this blog takes a little look at the nature of these disagreements.
Why can’t we all just be friends?
There are myriad factors behind the lack of consensus here, and it would be no fun for anyone to dive deep into them. For the sake of this blog, we’ll group some of the key contributors into the following reasons:
- a) we can’t answer some of the important questions, and;
- b) lots of people don’t want to answer (or acknowledge the answers to) some of the important questions.
The first category (“can’t”) is primarily because good quality nutrition research is difficult. To answer the most burning questions in nutrition would require long-term studies with lots of people where all the most important inputs and outputs are measured and controlled. This is essentially impossible, for a range of financial and logistical reasons. We are therefore left trying to make decisions based on partial information from studies with significant limitations.
The second category (“won’t”) is usually less well-meaning. There are significant conflicted interests in this field, with big business standing to gain or lose significant amounts of money based on public perceptions of what they should or shouldn’t be eating. Similar is true of many individuals who have books to sell or platforms to promote. In these cases deliberate obfuscations are par for the course, and this muddies the waters considerably.
Also in the “won’t” category is a less deliberate, but no less problematic, issue. This is related to subconscious biases people hold. These biases lead people to accept information that supports their beliefs and reject anything that challenges them. This is worsened by an echo chamber effect, where people surround themselves with like-minded people who reinforce their views, even where they are incorrect. These echo chambers might be “in the real world”, or in social media spaces (i.e., through only following people who promote the positions already held). These problems can, unfortunately, affect researchers and practitioners as well as members of the public.
Can’t or won’t, deliberate or subconscious, the net effect is division and confusion that is difficult to overcome. This is how we find ourselves where we are, with conflicting messages, polarised views, and false dichotomies everywhere. This is how we end up in a world where it is difficult to know what to believe, and therefore difficult to know what to do.
But “Schrödinger’s Fat”? What are you on about…
Like all good nutrition blogs, we are now going to take a little detour through the world of quantum mechanics.
Many of you will be familiar with the concept of “Schrödinger’s Cat”, which has been brought to a wider audience through television programmes such as The Big Bang Theory. But for those who are not familiar, I will use my limited and no doubt flawed understanding of quantum physics to try to give you the gist. This hypothetical scenario was concocted by Erwin Schrödinger, a Nobel Prize-winning physicist, as a way to explain one of the interpretations of quantum mechanics. In this thought experiment, a cat is sealed in a box with a flask of poison. We do not know if this flask has been broken, and thus we do not know if the cat is alive or dead. Based on the Copenhagen interpretation of quantum mechanics though, Schrödinger’s cat is both alive and dead until we open the box, as a quantum system exists in all states (and thus the flask is both broken and unbroken) until it is observed. Simple, right?
So, coming back to the somewhat tortured metaphor that provides the title of this blog, it often feels like the fat in our diet can be treated the same way as Schrödinger’s cat. It is both “good” and “bad”, depending on who you believe. That is to say, the claims related to dietary fat are often completely contradictory, depending on who you ask:
- Fat makes people feel full, yet it makes them hungry;
- Fat makes people gain weight, but it doesn’t make them fat;
- Fat causes heart disease, but it doesn’t clog up people’s arteries.
- Fat is simultaneously the cause of, and solution to, all of life’s problems. Hence, “Schrödinger’s Fat”.
Now of course the truth is much more nuanced than either of these extreme positions. There are dozens of different types of fat, contained in varying proportions in thousands of different foods alongside millions of combinations of other nutrients, which can be eaten with other foods in innumerable different combinations and quantities. To say fat is “good” or “bad” completely misses the point, yet that is often what messages are boiled down to.
The current state of the nutrition world rarely allows for this nuance to be discussed however, so oversimplifications and arguments remain. Almost all dietary messaging has a dissenting side – even advice that seems widely accepted, such as the role of non-starchy vegetables in a healthy diet, has those who would argue against it.
Keeping the physics theme of the blog, it is almost Newtonian (…equal and opposite reaction).
What Should I Eat Then?
The mindset discussed so far largely picks the wrong battles. If people gave up trying to demonise individual nutrients, but instead considered the effects of actual foods (people do after all eat food, rather than nutrients in isolation), it is likely that more helpful dietary advice could be provided*. Although there is value in open-minded research and debates into the effects of individual dietary components, for the average person it is much more practical to focus on foods and dietary patterns.
When it comes to food, trying to avoid ultra-processed foods, and choosing minimally processed options instead, would go a long way towards helping many people achieve their health goals.
When it comes to dietary approaches, there are a range of options that can be suitable. This includes low carb, Mediterranean, and low fat approaches. What is right for one person might not be the best option for someone else though. Personal needs and preferences are important*, as they will define the likelihood that any given individual will be able to stick to any given approach long-term.
For further information on these points, why not take a look at our “What I Need To Know” leaflet series. This series includes information on a range of different dietary approaches, as well as guidance on how to tell the difference between real and ultra-processed foods.
What’s the bottom line?
The field of nutrition is a minefield, with conflict and confusion around every corner. There is no better reflection of this when it comes to macronutrients – are fats, carbs and/or protein healthy? It depends on who you ask! Hence ““Schrödinger’s Fat”, where dietary fat will both harm us and heal us, apparently.
It is often possible to cut through this mess though. Such debates are often academic, and regularly focus on the wrong things. The practical take home message here (and ultimately in much of our content) is very much that dietary patterns and food quality are usually more important than becoming obsessed with individual nutrients, and they are certainly more important than petty arguments over the effects of them!
* This is not to say that consideration of individual nutrients is never valid. Sometimes individual needs are determined by individual physiology, which can result in a reduced ability to tolerate or metabolise certain nutrients. For example, many people with type 2 diabetes would likely benefit through reducing their carbohydrate intake. This does not undermine general messages around the importance of choosing minimally processed foods, but it can influence which foods would be the most appropriate choices within this context.