“Ultra-processed foods causing a ‘tidal wave of harm’ – says experts”
“The alarming truth about processed foods”
“Ultra-processed foods linked to 32 harmful effects to health, review finds”
These headlines are certainly eye catching, exactly what they’re designed to do. And if you were to take what the newspapers report at face value, you would have every right to run away from ultra-processed foods (UPF’s) with fear, but what is the truth?
Why the recent headlines?
You may have seen in the news that UPF’s are once again the talk of the town. The reason for this is a study that was recently published - Ultra-processed food exposure and adverse health outcomes: umbrella review of epidemiological meta-analyses
Now this article is not a critique of the paper, but a way of explaining the study and what it really means, for you, in the real world to the best of my ability.
What was the study?
The study was an “umbrella review of epidemiological meta-analyses”. The first thing to understand is what a meta-analysis is. In simple terms it is a type of study that looks to answer a very specific question by looking at the results of a combination of individual studies. They are seen as the gold standard in research and often provide a clearer summary of results, clearing up conflicting claims in individual studies.
This umbrella study included 14 meta-analyses which had looked at the impact eating UPF’s have on different health conditions including obesity, type 2 diabetes, mental health, gut health and mortality.
The studies included spanned a total of 9,888,373 people across the world.
What did the study find?
On the surface, the study found that the odds of you having a poorer health outcome increased in 71% (32) parameters measured in those who ate UPF’s compared to those that didn’t, or those that ate more. They found that the odds or risk increased by the following:
Health condition | Increased risk as a % |
All cause mortality (total deaths) | 21% |
Cardiovascular disease related deaths | 50% |
Cancer (overall) | 12% |
Adverse sleep | 41% |
Anxiety | 48% |
Common mental health disorders | 53% |
Cardiovascular disease | 35% |
Overweight | 36% |
Obesity | 55% |
Type 2 diabetes | 40% |
Those are quite damning statistics right?
You read that and you think, the chances of dying from cardiovascular disease increases by 50% if you eat processed foods, or your risk of getting Type 2 diabetes increases by 40%.
I can totally understand why reading these figures in a newspaper would really worry people and make them rethink eating any processed foods.
But one key skill you are taught as a Dietitian, is to always ask questions and take a measured look at the evidence before drawing any conclusions.
There are many questions I have when I read studies like this and many caveats that need to be spoken about, which makes the picture clearer.
Why should the results be taken with a pinch of salt?
Question 1: How reliable are these studies?
Nutritional epidemiology studies are population-wide studies that measure outcomes e.g. Type 2 diabetes over a long period of time in relation to nutritional intake. It is classed as an observational study because they are simply observing what happens over a period of time in the real world, without controlling any aspect of the study. These types of studies are often criticised due to their inability to measure diet accurately.
A difficulty with nutritional observational studies is they seek to find a cause but really, can only highlight correlations. For example, the aim of the studies used in this research were looking at the impact of processed foods on health, therefore when you see risk increases by 50%, you assume that it was the processed foods that cause it right?
Well what if I told you, evidence shows us the odds of you getting sunburnt increase on days more ice cream is bought…does that mean ice cream causes sunburn? Or could it be both are linked (correlated) to the cause (sunshine).
Therefore, could eating more processed foods be linked to anything else that increases the odds of poor health? E.g. poorer lifestyle choices such as not exercising, smoking, drinking?
Studies do use equations to try account for these other lifestyle variables, but they can not always fully do so.
So, nutrition observational studies are downgraded in terms of the quality of the evidence they provide. Therefore, even though the evidence linking increased ultra-processed foods and Type 2 diabetes, poor sleep, mental health and cardiovascular mortality is deemed as convincing, the studies are graded from very low quality to moderate, which does leave a question of doubt.
Question 2: How accurate is the data collected on the amount of processed foods eaten?
The main limitation of these kinds of studies is how they collect dietary data. They use food-frequency questionnaires (FFQ’s), 24hr dietary recalls and diet history. Now if I was to ask you what you had to eat yesterday, you may be able to recall this, but if I asked you to complete a FFQ and request you to tell me on average, how many portions of specific foods you have had this year, it would start to become trickier. These methods require participants to have a great memory as well as be able to work out averages of consumed foods and even more importantly…honest, something I know from my own research of food diaries, is rare.
Therefore, if the data on how much processed food is eaten in the first place is inaccurate, how can you be so sure as to its effects? It is very possible people are eating more than they are reporting, meaning the impact is likely to be even less.
Question 3: What foods are classed as ultra-processed foods?
Ultra-processed foods as defined by the NOVA -classification are “industrial formulations made entirely or mostly from substances extracted from food (proteins, starches, fats, oils etc..) or synthesis in labs from food substrates or organic sources including flavour enhancers, colours and additives).
Examples include:
· Packaged snacks – savoury / sweet
· Biscuits
· Ice cream
· Pre-packaged meat, fish, veggies
· Ready meals
· Pizzas
· Whey powder / ready mixed drinks
· Chocolate / sweets
· Patries / cakes
· Fizzy drinks / sweetened juices
· Cereals
· Distilled alcoholic beverages e.g. whisky, vodka, rum
Now although the research does show that there clearly is a link between UPF’s and adverse health, they also point out that other studies have found UPF’s including dark/brown bread, ultra-processed cereals, packaged sweet and savoury snacks and yoghurt were shown to have the opposite effect on health…but again, take this with the same measure of salt.
What is important to take away from this is, not all UPF’s are likely to be equal.
Look at the difference between the ingredients list of a lasagna ready meal and a twinky (not sure what one of these is? Go have a nosey). Both are ultra-processed, but would you say they are equal?
Question 4: What does a 50% increase in odds actually mean?
Now, this MAY be one of the most important points.
As I said earlier, the increased odds of getting adverse health is scary reading…however, we need to discuss this in greater detail.
This study looked at the odds of someone getting the condition if they weren’t exposed to processed foods compared to the odds of those that were.
To understand what the actual, potential damage is, you first have to understand absolute risk and the chances of getting ill in the first place.
Let’s take flipping a coin as an example. It can only be heads or tails so the chance of it landing on heads is 50%.
Theoretically, if we flipped the coin 100 times, it would land on heads 50 times.
Therefore, a 50% increase in odds would mean it would land on heads 75 times out of 100, something I wouldn’t bet against happening.
However…our health isn’t as simple as heads or tails. The chances of us getting cancer, Type 2 diabetes or a mental health condition are not 50/50.
What if the chances were 1 in 100 or 1 in 1,000,000?
A good example of this is the link between red/processed meat and lifetime risk at the age of 50 for colorectal cancer.
The odds of getting colorectal cancer in your lifetime, from 50 onwards is 1.8%. A study found for every 100g increase in processed red meat consumed, those odds increased by 14% but in reality, that means for over 50’s eating 100g of processed red meat a day, the odds become 2.1%. So just under 2% of over 50’s will get colorectal cancer anyway, just over 2% will do so if they eat processed red meat…Sometimes, the increased risk looks dramatic but the reality can be very different.
Question 5: What is it about ultra-processed foods that could cause poor health?
The study suggests 2 likely reasons:
Firstly, the alteration of ingredients by intensive processing, may alter the way we absorb and digest nutrients as well as effecting our gut microbiome, which although not fully understood, is something we are learning has an important role to play in both our physical and mental health. Moreover, additives and alternatives such as sweeteners are constantly scrutinised with continuous research on their links to how they effect our health, although evidence on the whole is not conclusive one way or the other as it stands and further research is required.
Secondly, ultra processed foods have a poorer nutrient profile – higher Calories, saturated fat, sugar, sodium whilst lower in protein, vitamins and minerals. This therefore is linked to increased weight, obesity and other health conditions such as Type 2 diabetes. There is also the argument for those who eat a higher percentage of ultra-processed foods eating less wholefoods, rich in nutrients, vitamins and minerals.
So what does the study REALLY tell us and what does it mean for you?
The study shows there is a clear link between UPF’s and poor health, however, due to all the above, this evidence is far from conclusive, as the writers of the study state themselves. What it does do though is show that further research is needed, especially in what types of processed foods and ingredients are causing the greatest risk and that on a population-wide level, government policy should focus on reducing the amount of processed foods people eat.
My personal opinion on processed foods is simple. They are part of our every day life nowadays and I believe they have a place in our diets (if you want them to). Now I am not saying I am pro-processed foods, far from it, I always encourage people I work with to focus on basing their diet on nutrient rich wholefoods such as meat, fish, dairy, fruit, vegetables, legumes and natural fats. However, I also make sure people make room for foods they love. This is because it makes eating more enjoyable for the individual and in most cases, makes achieving better health easier to achieve.
Lets take ready meals as a great example. Are ready meals better than cooking a meal from scratch with fresh produce? Absolutely not. But if someone either doesn’t have the time, skill level or confidence to cook, then is a good quality ready meal, balanced with protein, carbohydrates and fats and Calorie controlled, better than the alternative…fast food or takeaways?
I wouldn’t promote overly consuming processed foods, but you also don’t need to fear them.
I work tirelessly to help improve people’s relationships with food, my experience tells me seeing food as “good or bad” and restricting foods can have extremely negative consequences.
Think of it like this, there are no good or bad foods but there are better investments.
Processed foods aren’t typically the best investment, but then again, it depends on what type and the reason for having it.
So no, processed foods will unlikely be the death of you.
Base your diet on wholefoods, keep a small space for processed foods and you will be happy and healthy, I am sure.
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