I want to talk about something that I think is one of the most important and most overlooked parts of the cancer conversation. Not treatment, not genetics, not bad luck — but the food that most of us have been eating every day for years, believing it was fine, or even good for us.
Ultra processed food. And why I think it's doing far more damage than most people realise.
The packaging lies
Walk down any supermarket aisle and you'll be confronted with packaging that screams health at you. High protein. No added sugar. Fat free. Low calorie. These products are marketed as the sensible choice, the healthy option, the thing a responsible person buys.
But here's what I've come to understand — when a manufacturer takes something out of a product, they almost always put something else in. Take out the sugar and sweeteners go in. Take out the fat and something else goes in to maintain the texture and palatability. Take out the calories and you're left with a product stuffed with things that were created in a laboratory, not a kitchen.
Our bodies have been eating real food for hundreds of thousands of years. They know how to process an apple or a piece of chicken. They have absolutely no idea what to do with half the ingredients on the back of a protein bar.
My Pepsi Max problem
I need to be honest about this because it's embarrassing in hindsight but it's also the kind of thing that I think a lot of people will recognise in themselves.
Before all of this I was drinking between two and four litres of Pepsi Max every single day. Every day. I rarely drank water because I always craved something with flavour. Pepsi Max felt like the responsible choice — no sugar, no calories. I genuinely thought I was being sensible.
Two to four litres a day. Of sweeteners. Every day. For years. I didn't know what I was doing to myself.
What I found when I started researching is that sweeteners, despite having no sugar, still produce an insulin response. The sweet taste on the tongue sends a signal to the body that sugar is coming. Insulin is released. But there's no sugar — so the insulin has nothing to work with. Over time this repeated misfiring leads to insulin resistance, which is one of the underlying conditions strongly linked to cancer growth, weight gain, and chronic inflammation.
On top of that, drinks like Pepsi Max actively strip the healthy bacteria from your gut. And your gut microbiome is not a minor thing — it is your body's primary defence system. Your immune system lives largely in your gut. I was essentially hosing down my immune system with something I thought was harmless.
Why ultra processed food makes you eat more
Ultra processed food is specifically engineered to be hyper-palatable. The combinations of salt, fat, sugar and chemical flavour enhancers are designed to keep you eating. That's not an accident — it's the product design.
But there's a deeper problem beyond just craving. Because ultra processed food is so thoroughly broken down before it even reaches you, your body absorbs it almost instantly. There's almost no digestive work required. This means blood sugar spikes rapidly, insulin follows, and because your gut and stomach haven't had to do much work, your brain doesn't fully register how much you've actually consumed. You're hungrier sooner. You eat more. The weight goes on.
Real food — food with fibre, with structure, with complexity — requires actual digestion. Your gut has to work. That work takes time, and that time is what tells your brain you've eaten. High fibre foods in particular feed the healthy bacteria in your gut microbiome and help them grow — including a microbe called Akkermansia, which research is now linking to positive outcomes in immunotherapy treatment. That one stopped me in my tracks when I read it.
Low level inflammation — the silent problem
The research I've done keeps coming back to two things as potential drivers of early onset cancer — chronic low level inflammation and insulin resistance caused by persistently high blood sugar. And both of these are significantly worsened by a diet high in ultra processed food and sweetened drinks.
I'm not saying this is what caused my cancer. I genuinely don't know that, and I'd never claim to. But I look back at what I was putting into my body — litres of Pepsi Max, processed foods that I thought were healthy choices — and I wonder. I can't help but wonder.
I abused my body for years with things I thought were fine. Things the packaging told me were fine. And the weight I've lost since switching to real food — without eating any less — tells its own story.
What I do now
I drink water. Sparkling water if I want something with a bit more to it, or green tea, which is genuinely one of the most polyphenol-rich things you can drink. I eat real food — things with one ingredient, things that grew somewhere, things my body recognises. I read labels not for the calorie count but for the ingredient list. If I can't picture what an ingredient looks like in nature, I put it back.
It's not complicated. It's just a different way of thinking about food — not as fuel to be optimised, but as information that your body uses to either defend itself or leave itself more vulnerable. Framed like that, the choice becomes pretty obvious.
As always — this is my personal experience and the research I've found compelling. It is not medical or nutritional advice. Please speak to your own medical team or a registered dietitian before making significant changes to your diet.
— Nick