I want to be absolutely clear before I write this — I don't know why I got cancer. Nobody does. There is no single definitive answer and I'm not a doctor. What I have is a theory, built from research, reflection and the benefit of hindsight. I'm sharing it because I think it might make some people think about their own lives. Not to scare anyone. But because I wish someone had made me think about mine a bit sooner.
My consultant told me he believed my tumour had been growing for at least three or four years before it was found. That puts its origins somewhere around 2020 to 2021. And when I look back at what my life looked like in that period, a picture starts to form.
It started before the kidney
In mid to late 2020 I was diagnosed with skin cancer — a mix of basal cell carcinoma and squamous cell carcinoma under my eye. It was caught and removed quickly. No further treatment needed. I didn't think much more about it at the time.
But looking back now — two cancers, developing at roughly the same time. That's not nothing. That's my body telling me something was wrong at a systemic level, not just in one place. And when I started researching what was happening in my life around that period, certain things stood out.
The factors — none alone, all together
Each of these things on its own is probably manageable. The body is resilient. But I think I was doing all of them simultaneously, and I think the cumulative effect on my immune system and overall health created exactly the kind of environment where cancer can take hold.
1 Shift work and chronic sleep deprivation
I was working at an Aldi distribution centre, up at 4am every day, constantly tired. At the time I noticed my skin cancer appeared and half wondered whether the early mornings were a factor. As it turns out — there is research to support exactly that. Studies have shown that shift work, particularly early morning shifts that disrupt the body's natural circadian rhythm, significantly increases the risk of developing certain cancers. Chronic sleep disruption suppresses immune function, raises cortisol levels and creates a state of persistent low level inflammation — exactly the kind of environment cancer needs.
2 A diet full of hidden sugar and ultra processed food
White bread. White pasta. Protein shakes. Pepsi Max. The list goes on. I thought I was eating reasonably — I wasn't eating takeaways every night or anything obviously terrible. But my diet was full of hidden sugars, refined carbohydrates that spiked my blood sugar constantly, and ultra processed foods that were destroying my gut microbiome without me having any idea. High blood sugar, insulin resistance and poor gut health are all independently linked to increased cancer risk. I was hitting all three, every day.
3 Overtraining on an exhausted body
I was already exhausted from shift work. And then I was coming home to do 30 minute Joe Wicks HIIT workouts five days a week before dinner. On my days off I was going for long runs or long bike rides. I was lean — almost scarily lean looking back at photos from that time. I checked my Strava records and the training load was significant. Exercise is good for you. Overtraining on a chronically exhausted body is a different thing entirely. It keeps your cortisol elevated, it suppresses your immune response, and it gives your body no time to repair. I was running on empty and then training on top of that. Something had to give.
I looked back at photos from that period and barely recognised myself. I was so lean it was unreal. At the time I thought I was being healthy. Now I think I was running my body into the ground.
4 COVID
This one is less certain but worth mentioning. I contracted COVID during this period. There is emerging research suggesting that COVID infection may increase the risk of certain cancers — not as a direct cause but as a trigger that can accelerate existing processes or further suppress immune function at a critical time. I'm not saying COVID caused my cancer. But I think it may have been one more thing hitting a body that was already struggling.
5 Destroyed gut health
Between the Pepsi Max, the ultra processed food and the high sugar diet, my gut microbiome must have been in a terrible state. Your gut is your immune system. The trillions of bacteria that live in a healthy gut are your body's first and most powerful line of defence — against infection, against inflammation, and against abnormal cell growth. I was systematically destroying mine every single day with things I genuinely thought were fine. That's probably the factor that bothers me most in hindsight.
The picture it paints
Take any one of those factors in isolation and most people would get through it fine. The body is designed to cope with stress, with bad diet, with disrupted sleep — for a while. But I was doing all of them at the same time, for an extended period, at a point in my life when I was in my early forties and my body's natural repair mechanisms were perhaps not quite what they'd been at 25.
Chronically disrupted sleep. Persistently high blood sugar. A destroyed gut microbiome. An immune system hammered by overtraining and COVID. And two cancers appearing at roughly the same time.
There is one more possibility I should acknowledge — genetics. It's possible I am simply predisposed to cancer and none of the above had any bearing on it whatsoever. Without a genetic test I can't rule that out. But there is no history of cancer in my family that I'm aware of, and the research increasingly suggests that genetic causes account for only around 15% of cancer cases. The vast majority — somewhere in the region of 85% — are now thought to be driven by environmental factors. Lifestyle, diet, exposure, habits. Things that are, at least in part, within our control.
That doesn't mean it's anyone's fault when they get cancer. It absolutely isn't. But it does mean that the way we live our lives matters more than most of us realise — and more than most of us are ever told.
I'm not angry about it. What would be the point. But I do think about how different things might have been if I'd known then what I know now. Which is exactly why I write about this stuff.
I can't change what happened. But if someone reads this and thinks twice about their sleep, their diet, their training load, their gut health — and takes one small step to address something — then this post has done its job.
Look after your body. It's the only one you've got.
This is my personal theory based on my own research and reflection. It is not medical opinion or established fact. Cancer is complex and multifactorial and nobody can say with certainty what causes it in any individual case. Please speak to your own medical team with any concerns about your health.
— Nick