When I watched Joe Wicks: My Killer Protein Bar on Channel 4, I had mixed feelings. Joe clearly wants to help people live healthier lives, and his enthusiasm for nutrition and exercise has inspired many. But good intentions don’t always make for good science. This documentary – dramatic, sensational, and worryingly inaccurate in parts – missed the chance to have a truly constructive conversation about how we eat, and why ultra-processed foods have become such a dominant part of our diets.
Intentions vs Execution
Joe Wicks’ heart may be in the right place. He clearly wants to raise awareness about what’s in our food and encourage healthier eating habits. But the approach taken in this documentary was unhelpful, oversimplified, and at times irresponsible.
It was particularly disappointing to see Dr Chris van Tulleken, a medical doctor, contributing to the same misleading narrative. The programme set the scene in a darkened lab, styled more like a “drug den” than a kitchen. With eerie lighting and dramatic music, it aimed to provoke fear rather than understanding. By portraying additives as if they were illicit substances, it spread confusion — a choice that was both misleading and unnecessarily alarmist.
This kind of presentation undermines public understanding of nutrition and makes serious issues about food systems look like entertainment.
What Ultra-Processed Foods Really Are
Ultra-processed foods, often called UPFs, are classified using the NOVA system — a way of grouping foods by how heavily they’ve been processed before reaching our plates. UPFs include foods that contain ingredients you wouldn’t typically find in a home kitchen, such as emulsifiers, stabilisers, sweeteners, and preservatives.
However, the NOVA system has its limitations. It often lumps together very different foods – for instance, a fortified wholegrain cereal and a chocolate bar could both be classed as “ultra-processed,” even though their nutritional value and contribution to health are vastly different.
This oversimplification can lead to confusion. Processing itself isn’t inherently bad – what matters is what the food provides nutritionally and how it fits within the overall diet.
What the Real Problem Is (and Isn’t)
From a nutrition perspective, the problem with UPFs is not the presence of additives. Within regulated limits, these substances are considered safe. The issue lies in the nutritional composition and ease of overconsumption.
UPFs are often:
High in fat, sugar, and salt
Energy-dense and low in key nutrients
Texturally easy to eat, making it easier to overconsume
This combination can contribute to excess calorie intake and poor diet quality. But that doesn’t mean every UPF is “bad.” When people rely heavily on these foods, it often comes at the expense of nutrient-dense, minimally processed options like fruits, vegetables, wholegrains, and pulses. That displacement – not the additives – is the real issue.
Additives and the Aspartame Claim
The programme’s treatment of aspartame was a perfect example of misinformation. Chris van Tulleken stated that the World Health Organization had said aspartame “causes cancer in humans.”
That’s not accurate.
The WHO’s International Agency for Research on Cancer (IARC) classified aspartame as a “possible carcinogen”, meaning there’s limited and inconsistent evidence. The classification simply acknowledges that scientists can’t rule out a risk, due to some low quality evidence in animal studies – not that it causes cancer.
The WHO’s food safety committee reaffirmed that aspartame is safe within the current acceptable daily intake. An adult would need to consume roughly 9–14 cans of diet soft drink per day, every day, to exceed those limits.
This is just one example of how the programme shaped information to support its own rhetoric, rather than presenting the full context. It wasn’t the only instance — several other claims could also be reasonably challenged. Misrepresenting this nuance erodes trust in science and distracts from the real nutrition priorities that would actually help people.
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The Poison Is in the Dose
One of the most misleading ideas in the documentary was the suggestion that a single protein bar could somehow “kill you.” That kind of statement may make good headlines, but it’s scientifically absurd.
In toxicology and nutrition alike, the principle is simple: the dose makes the poison. Almost any substance -from vitamins to water -can be harmful in excess, and harmless in moderation. The same applies to the ingredients found in most processed foods.
Additives, preservatives, and sweeteners are heavily regulated in the UK, with strict limits on how much can be safely used in food. Within those limits, there’s no credible evidence that a protein bar -or any single product -poses a danger.
What matters is pattern and quantity over time. Eating high-fat, high-salt, high-sugar foods in large amounts, and doing so consistently, can contribute to poor health outcomes. But suggesting that one snack, consumed occasionally, is a “killer” food undermines the complexity of nutrition science and fosters unnecessary fear.
Where Additives Come From – and Why That Matters
Another key point missing from the documentary is that many additives come from natural sources.
For example:
Lecithin can be extracted from egg yolks or soybeans.
Monoglycerides often come from plant or animal fats.
Xanthan gum is produced by fermenting natural sugars with friendly microorganisms.
So, while some additives are made synthetically for consistency and cost reasons, many have natural origins. The idea that they’re all “lab-made chemicals” is again misleading.
That said, it’s still appropriate to continue researching these compounds and reviewing their safety – science evolves, and vigilance is important. But at present, the regulatory frameworks in the UK and EU are robust, and additives are considered safe within established limits.
Why Demonising Foods Is Harmful
Scare tactics around food don’t help people eat better – they just make them anxious. There’s already a significant amount of food-related anxiety in the UK, particularly among those who care deeply about their health.
The people most harmed by this messaging, however, are those with the fewest resources. For families living on tight budgets, shelf-stable foods are often the only practical option. Making them feel guilty for feeding their children affordable, safe, regulated foods is simply unhelpful.
The problem isn’t the individuals making these choices; it’s the food environment and socioeconomic inequality that limit their options.
We need policies and education that make healthy choices more realistic and affordable for everyone, not shame or fear-based messaging that deepens inequality.
The Fibre Factor: What’s Really Missing
One of the key nutritional differences between a diet high in UPFs and one rich in whole foods is the balance of nutrients – particularly fibre.
The issue isn’t that UPFs contain no fibre (some, like beans or fortified cereals, do), but that when people eat a lot of UPFs, they tend to eat fewer fruits, vegetables, wholegrains, and legumes – the primary sources of dietary fibre and micronutrients.
This displacement matters because higher fibre intake is strongly linked to lower disease risk. Increasing fibre by just 7 grams per day – the equivalent of about half a can of beans or lentils – is associated with:
9% lower risk of cardiovascular disease
7% lower risk of stroke
8% lower risk of colorectal cancer
Fibre also helps manage blood sugar and cholesterol, supports digestive health, and promotes fullness.
Yet only around 9% of UK adults meet the recommended 30g per day, according to the NHS. That shortfall has far greater public health consequences than any trace of approved additives in the food supply.
The Bigger Picture
If we truly want to help people eat better, we need to shift the conversation away from chemical scapegoats and towards the structural barriers that make unhealthy eating patterns the norm.
That means:
Making nutritious foods affordable and accessible
Investing in education and cooking skills across all communities
Addressing poverty and inequality as fundamental health issues
Supporting responsible innovation in food production, rather than demonising it
Additives and processing technologies have enabled longer shelf life, reduced food waste, and improved access to safe, affordable food for millions. Removing these tools would not solve our health challenges – it would worsen them.
A Balanced, Realistic Approach
As a nutritionist, my TL;DR is this:
Yes, I encourage people to eat a mostly whole-food diet wherever possible – rich in fruits, vegetables, wholegrains, legumes, nuts, and seeds. But I also recognise that we live in a modern world, with busy lives, tight budgets, and diverse needs.
Including some convenient, tasty, and regulated processed foods isn’t something to fear – it’s part of a balanced approach to eating. What matters most is dietary pattern and proportion, not perfection.
We need a grown-up conversation about food systems, access, and health – not more fear about protein bars.
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The information in this blog is for general information only and should not be used as individual advice. Advice may vary for certain medical conditions and the information in this article is not intended to replace or conflict with the advice given to you by your GP or other health professionals. All matters regarding your health should be discussed with your GP. If you or someone you know may be suffering from an eating disorder, then please seek professional help.
