By George Jackson, MSc
Cancer is one of the most feared and complex diseases in the modern world.
While often framed as a consequence of genetics or ageing, growing evidence suggests that cancer development is strongly shaped by the internal biological environment created by diet, lifestyle, and environmental exposures.
At its core, cancer arises when damaged cells are no longer effectively repaired or eliminated, allowing them to proliferate uncontrollably and form tumours that spread throughout the body.
While genetics can influence susceptibility, cancer is increasingly understood as a largely epigenetic process – more influenced by how we live our lives and the everyday choices we make.
This perspective reframes cancer not as a sudden event, but as the downstream outcome of long-term metabolic, inflammatory, and cellular stress.
Fortunately, many of these factors are within our control.
By addressing dietary, lifestyle, and environmental drivers, and understanding the biological mechanisms involved in cancer development, it’s possible to reduce risk by supporting the body’s natural ability to maintain cellular order and resilience, creating an internal environment in which cancer cells struggle to thrive.
Rising Incidence Rates of Cancer
Globally, cancer incidence has risen steadily in recent decades, with increases that cannot be explained by population ageing alone.
Age-standardised data indicate that independent of population growth, true cancer risk is increasing, particularly among younger adults.
In 2022, an estimated 20 million new cases were diagnosed worldwide, corresponding to an age-standardised rate of approximately 197 per 100,000 people — an 8.2% increase from 2012.
These trends are projected to accelerate, with annual cases expected to reach 35 million by 2050 – a 77% increase from the cancer cases reported in 20221.
While population growth contributes to this rise, age-standardised data show that true cancer risk is increasing across many regions.
Since the 1990s, incidence rates have risen by around 25–30% in lower-income countries, even after accounting for demographic change.
Cancer is also developing earlier in life. Although around two-thirds of cases still occur in those over 60, early-onset cancers (under 50) have increased by nearly 80% since 19902.
These trends suggest that prolonged exposure to modern lifestyle and environmental stressors is influencing disease development at younger ages.
Importantly, this rise is not inevitable.
Many of the underlying drivers of cancer – including metabolic dysfunction, chronic inflammation, obesity, poor diet quality, physical inactivity, alcohol consumption, and environmental toxins — are modifiable, highlighting the significant role of epigenetics over genetics.
Together, these trends point to a clear conclusion: the global cancer burden is expanding at a pace that demands a stronger focus on prevention.
Reducing risk requires more than early detection and treatment — it depends on proactively addressing the biological and environmental conditions that enable cancer to develop in the first place.
External Factors that Drive Cancer
Cancer does not develop in isolation. In most cases, it is the result of long-term exposure to factors that place stress on the body, disrupt normal cellular function, and create conditions in which abnormal cells can survive and multiply.
Diet
Modern dietary patterns strongly correlate with cancer risk. Diets high in refined sugars and additives, ultra-processed foods, and unhealthy fats promote chronic inflammation, oxidative stress, and insulin resistance — key biological conditions linked to cancer development.
Excess sugar intake is particularly problematic as repeated spikes in blood glucose and insulin create a metabolic environment that favours growth. Over time, this metabolic instability contributes to conditions that are increasingly linked to cancer development.
Highly processed foods also tend to be low in fibre, antioxidants, and phytonutrients, depriving cells of essential compounds that play protective roles in cellular health and DNA repair.
In contrast, a balanced, whole-foods based diet provides a diverse range of bioactive compounds that help regulate cellular stress, support detoxification pathways, regulate inflammation, and maintain metabolic balance.
Lifestyle
Physical inactivity, chronic psychological stress, poor sleep, and obesity all place strain on key biological systems to further compound cancer risk.
A sedentary lifestyle is associated with impaired circulation, reduced immune surveillance, and hormonal imbalances.
Chronic stress elevates cortisol and inflammatory signalling, which over time can weaken immune function and disrupt normal cell regulation.
Sleep disruption interferes with circadian rhythms that are essential for DNA repair and cellular regeneration.
Excess body fat promotes inflammation and influences hormone levels, particularly insulin and oestrogen, both of which are linked to cancer progression.
Environment
Chronic exposure to environmental toxins is an often-overlooked contributor to cancer risk.
Everyday contact with chemicals, pollutants, pesticides, heavy metals, microplastics and endocrine disruptors can damage DNA, interfere with hormone signalling, and overwhelm the body’s detoxification systems.
These toxins may be encountered through food, water, plastics, clothes, household products, and personal care products.
Over time, cumulative exposure can increase oxidative stress and impair the body’s ability to eliminate harmful substances efficiently.
Crucially, many of these exposures are both identifiable and modifiable.
Understanding where toxins are present in your environment – and how to reduce or replace them with safer alternatives – is a key part of lowering long-term disease risk.
Biological Mechanisms That Drive Cancer
While external factors initiate stress, cancer ultimately develops through a series of internal biological mechanisms that determine whether damaged cells are repaired, eliminated, or allowed to grow unchecked. When these systems become chronically disrupted, the risk of cancer increases significantly.
DNA Damage and Impaired Repair
DNA damage is a constant occurrence, but under healthy conditions it is efficiently repaired or the affected cell is removed. Chronic exposure to toxins, inflammation, and oxidative stress can overwhelm these repair systems, allowing mutations to accumulate and persist.
Chronic Inflammation
Inflammation is an essential immune defence, but when it becomes chronic it creates a pro-growth environment for abnormal cells. Persistent inflammatory signalling encourages cell proliferation and inhibits normal cell death, increasing the likelihood that mutated cells will survive and expand.
Dietary factors, obesity, chronic stress, poor sleep, and environmental toxins are all major contributors to long-term inflammation.
Oxidative Stress
Oxidative stress occurs when the production of free radicals exceeds the body’s ability to neutralise them with antioxidants. Free radicals can damage DNA, proteins, and cell membranes, accelerating mutation rates.
Diets low in antioxidant-rich foods and high in processed ingredients, combined with toxin exposure and metabolic dysfunction, significantly increase oxidative stress levels.
Metabolic Dysregulation and Insulin Signalling
Cancer cells have altered metabolism and rely heavily on glucose for energy. Consistently elevated blood sugar and insulin levels — common in diets high in refined carbohydrates and sugar — act as a continuous growth signal, promoting cell division and inhibiting normal regulatory controls to encourage tumour growth.
Immune Surveillance Dysfunction
A healthy immune system routinely identifies and removes abnormal or pre-cancerous cells. Poor nutrition, chronic stress, sleep deprivation, and toxic overload impair this surveillance, allowing damaged cells to evade detection and proliferate.
Hormonal Imbalance
Hormones regulate growth, metabolism, and cellular communication. Disruption to hormonal balance — particularly insulin, oestrogen, and cortisol signalling — can increase the risk of hormone-sensitive cancers.
Excess body fat, chronic stress, and endocrine disrupting chemicals from the environment all contribute to hormonal dysregulation.
Overburdened Detoxification Systems
Detoxification systems become overburdened when the liver, kidneys, gut, and lymphatic pathways are continually exposed to cumulative toxins, food additives, pharmaceutical residues, and metabolic waste, exceeding the body’s ability to safely process and eliminate them.
This overload allows toxic, pro-inflammatory compounds to accumulate, promoting DNA damage, oxidative stress, and hormonal disruption – all permissive for cancer development.
Mitochondrial Dysfunction
Mitochondria regulate energy production, cell signalling, and programmed cell death. When mitochondrial function declines, cells may shift toward inefficient energy pathways that favour survival despite damage.
This metabolic shift is a recognised feature of many cancers, allowing cancer cells to survive in hostile environments and continue proliferating despite cellular damage.
Chronic inflammation, oxidative stress, nutrient deficiencies, and toxin exposure all impair mitochondrial health, weakening the cell’s ability to regulate growth and self-destruct when necessary.
Supporting Cellular Resilience Through Lifestyle Biology
The biological cancer-promoting mechanisms are shaped by the external signals the body receives daily. Removing or reducing stress signals can shift the internal environment away from one that favours abnormal growth and toward one that supports cellular repair and resilience.
Reducing Inflammation and Oxidative Stress
Removing inflammatory dietary inputs — such as excess sugar, ultra-processed foods, industrial seed oils, and excessive alcohol — can substantially lower inflammatory signalling. Replacing them with an anti-inflammatory diet consisting of whole, nutrient-dense foods rich in antioxidants and fibre helps alleviate oxidative stress and stabilise immune and metabolic responses.
Adequate sleep, regular physical activity, and stress management further reduce inflammatory load and oxidative stress.
Restoring Metabolic Balance
Lowered refined carbohydrate and sugar intake helps stabilise glucose levels to improve insulin sensitivity, limiting growth-promoting signals to abnormal cells.
Exercising regularly and maintaining healthy sleep patterns also improve glucose regulation. Periods of metabolic rest, such as intermittent fasting, may further enhance metabolic flexibility, limiting the fuel availability preferred by cancer cells while remaining favourable for healthy cells.
Strengthening Immune Surveillance
Immune function improves when the body is well-nourished, well-rested, physically active, and not chronically stressed. Reducing toxic exposure, supporting gut health, and correcting nutrient deficiencies enhances the immune system’s ability to identify and eliminate abnormal cells before they progress.
Maintaining Hormonal Balance
Remove hormone-disrupting chemicals from your environment by choosing glass or stainless-steel food containers, avoiding plastic food packaging and non-stick cookware, and using fragrance-free, naturally formulated personal care and household products. Minimising excess body fat reduces insulin and oestrogen dysregulation and actively managing chronic stress prevents sustained cortisol elevation.
Reducing Toxic Load and Supporting Detoxification
Limit toxin exposure by drinking filtered water, avoiding processed foods, purifying indoor air, and swapping out chemically loaded personal care and home products to reduce toxin-induced cellular damage and hormonal disruption.
Support detoxification pathways — particularly liver and gut function — through hydration, fibre intake, nutrient-dense foods, with adequate movement and sleep, to enhance the elimination of harmful compounds and restore normal cellular communication.
Improving Mitochondrial Health
Mitochondria respond positively to regular, appropriate stress followed by recovery. Physical activity stimulates mitochondrial biogenesis, increasing both the number and efficiency of mitochondria. Adequate sleep and circadian rhythm alignment are equally important, as mitochondrial repair and regeneration occur most effectively during rest.
Nutrient-dense diets supply essential nutrients required for energy production and antioxidant defence. Practices such as intermittent fasting, temperature exposure, minimising toxin exposure, and stress reduction also enhance mitochondrial integrity and efficiency.
Prevention is not passive – it is built through repeated biological signals that compound over time.
A Prevention-Focused Perspective
Cancer reflects the cumulative interaction between biology and environment over time.
By understanding the biological mechanisms that drive cancer, it becomes clear that many of the key drivers are modifiable.
Focusing on nutrition, hydration, prioritising sleep, exercising, managing stress, and reducing toxic exposure, as well as practices like intermittent fasting and temperature therapy, provides a useful framework to improve the efficiency of these biological mechanisms to help create an internal environment that is far less favourable to cancer development.
These strategies are not about extreme measures or fear-driven choices.
They are about supporting the body’s innate capacity for regulation, repair, and resilience through consistent, sustainable lifestyle choices.
While conventional medical treatments remain the primary mode of care for diagnosed cancers, addressing these foundational biological processes plays a meaningful role in reducing risk, supporting recovery, and promoting long-term health.
Ultimately, protecting against cancer is less about fighting disease and more about creating the conditions in which healthy cellular function can thrive.
By George Jackson, MSc
Reference
1. GLOBOCAN 2022: Estimated cancer incidence, mortality and prevalence worldwide. World Health Organization. https://gco.iarc.fr/
2. Vos, T., et al. (2023). Global burden of early-onset cancer (1990–2019). BMJ Oncology. https://doi.org/10.1136/bmjonc-2023-000049
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