Cancer Risk, Inflammation & Diet:What the Evidence Really Shows

A few years ago, I did “everything right” (at least on paper). I was eating a mostly whole-food, plant-based diet. I was moving my body. I was trying to live the wellness life.

…and I still got diagnosed with cancer.

That moment taught me something I really needed to learn:

Food is powerful — but it’s not magic. Diet can lower risk and support the body, but it can’t guarantee outcomes. (And if anyone tells you otherwise, please back away slowly.)

Remember, I am a geeky scientist by training (and genetics! LOL) so, let’s talk about what the evidence actually shows about inflammation, diet, and cancer risk, without fear, without fluff, and without turning meals into a moral test.

I’ve also included the scientific sources at the end of this blog so you can read the actual peer-reviewed published study for yourself.  I’m all about empowering you to form you own conclusions which helps supports and motivates you in your health and wellness journey.

First: What is inflammation (in plain English)?

Inflammation is your body’s alarm system.

• Short-term inflammation (like healing a cut) = helpful.

• Long-term low-grade inflammation = can be a problem.

Chronic inflammation can create a body environment that supports cancer development and progression over time (it can affect DNA damage, immune function, and cell growth signals). (You’ll see this reflected in major cancer prevention reports and biomarker research.) [1][2]

A common blood marker for inflammation is C-reactive protein (CRP). I always include this blood analysis when I have blood work done.  It’s covered by most insurance so you may want to ask your medical professional to include it in your annual checkup blood work. 

Higher CRP is linked with higher risk of worse outcomes (including cancer-related outcomes) in large analyses, though it’s not the only factor and doesn’t prove cause by itself. [2]

What the evidence says diet can do

1) Diet can reduce cancer risk, especially through patterns

Cancer prevention science isn’t about one “superfood.” It’s about patterns you repeat.

The World Cancer Research Fund (WCRF) emphasizes a pattern of:

• whole grains, vegetables, fruit, beans

• limiting fast foods/ultra-processed foods

• limiting red and processed meat

• limiting alcohol

• staying active and keeping a healthy weight

  
  

  …as core cancer prevention recommendations.[1]

In other words: It’s probably everything you’ve heard before – but it’s all scientifically backed recommendations. How can we ignore this?

2) Ultra-processed foods are consistently linked with higher risk

Ultra-processed foods (UPFs) aren’t just “food that comes in a package.” They’re industrial formulations, often with additives, emulsifiers, refined starches/sugars, and low fiber.

A major BMJ umbrella review (2024) found UPF exposure was associated with many adverse outcomes, including cancer outcomes in the overall evidence map (observational evidence; not proof of causation). It’s one of the most comprehensive “big picture” summaries we have right now. [3]

A separate 2023 systematic review found consistent associations between higher UPF intake and risk of overall and several cancers (including colorectal and breast), again largely from observational studies. [4]

Translation: This doesn’t mean you’re doomed if you eat chips. It means your everyday pattern matters, and reducing UPFs is a powerful lever.

3) Processed meat has the clearest “avoid/limit” cancer signal

This is one of the strongest, clearest statements in nutrition science:

The International Agency for Research on Cancer (IARC/WHO) classified processed meat as carcinogenic to humans (Group 1) based on sufficient evidence that it causes colorectal cancer.[5][6]

This doesn’t mean “a bite of bacon = cancer.” It means the evidence is strong enough that public health organizations recommend limiting it. [1][5]

Despite the overall evidence, I continue to see tons of ads on TV, magazines and even on cooking shows regarding cooking and consuming known human carcinogens like hotdogs and especially bacon.  This isn’t meant to be a moral judgement, (but it may sound like a judgement anyway) it confounds me that a parent can feed their child a known carcinogen and then be up in arms when they find out that some industry is spraying apples with pesticides or that there is a gas station a mile from their house and they are worried that the fumes can cause cancer for their kids. 

An industry spraying apples or the location of a gas station close to your home may not be in you direct control. Feeding your child bacon is definitely and completely in your control.  If you have gotten this far in my blog – and thank you for that! – then please give this one statement some serious thought.

Okay, back to not judging or stepping down from my soap box.

4) Fiber-rich, plant-forward eating is consistently protective

If you have read any of my blogs or have attended any of my nutrition or cooking classes you know this is a BIG topic for me.  It’s basically the only message that I share that would benefit you the most.  Fiber is not glamorous. Fiber is not trendy. Fiber does not have good PR.

But fiber is quietly one of the most consistent diet factors linked to better long-term health, including lower cancer-related mortality risk in meta-analyses. [7]

Fiber also supports gut bacteria that produce helpful compounds (like short-chain fatty acids), which can influence inflammation and gut barrier integrity, two things that matter for long-term health. [8]

5) Anti-inflammatory patterns (like Mediterranean-style) show benefits

Mediterranean-style diets (plant-forward, lots of fiber, nuts/olive oil, legumes, fruits/veg) have evidence for reducing inflammatory markers in randomized controlled trials (stronger type of evidence than observational studies). [9] I do need to emphasize that consumers have locked in on the olive oil part and less on the fruits, vegetables and nut part.  Also, these studies show that lifestyle plays a big role too.  Less stress, more walking or physical exercise and, this is another big one, community.

I won’t get into it here, but there are a ton of studies out there showing high consumption of pure vegetable oils is one of the main culprits in inflammation.  100% fat, highly processed, minimal nutrient value and absolutely no fiber. The fat on your lips goes straight to your hips. I’ll talk about that another time. Stay tuned. Or message me if you want more info.

Back to my original topic.  Meta-analyses (which is a comprehensive review of the peer-reviewed scientific published literature on this topic) continue to report associations between higher Mediterranean diet adherence and lower incidence for certain cancers (effect sizes vary by study and cancer type). [10][11]

If “anti-inflammatory eating” sounds vague, think:more plants, more fiber, fewer ultra-processed foods, less processed meat, less alcohol. [1][3][5]

What diet doesn’t do (and this matters)

 Diet does NOT guarantee cancer prevention.  Even with excellent habits, cancer can still happen due to:

• genetics

• random mutations

• environmental exposures

• hormones

• infections

• age

• and factors we don’t fully understand yet

So, if you’ve ever looked at someone’s diagnosis and thought, “But they were so healthy…” yes. Exactly. Healthy habits are not a shield of invincibility. They’re risk reducers and body supporters. [1]

The “Do This This Week” Action Plan (simple + powerful)

✅ 1) Add a fiber anchor daily

Pick one:

• ½ cup beans or lentils

• 1 cup oats

• 2 cups veggies

• 1 cup berries

• 1 baked potato + a big salad

(Your gut bacteria will write you a thank-you note.) [7][8]

✅ 2) Swap ONE ultra-processed habit

Examples:

• soda → sparkling water + citrus

• packaged snack → fruit + nuts

• frozen meal → simple bean chili batch

• sugary breakfast → oats + fruit

You don’t need a new personality. Just one better default. [3][4]

✅ 3) Choose “mostly plants” as your baseline

Not perfection. Not pressure. Just a default direction that matches the evidence. [1]

✅ 4) Get curious about alcohol and processed meat

This is not a shame statement. It’s an evidence statement. If you want the strongest cancer-prevention moves, these are the two to look at first. [1][5][6]

Takeaways (save this)

• Inflammation is your alarm system, chronic inflammation matters. [2]

• Cancer prevention is mostly about patterns, not magic foods. [1]

• UPFs show consistent links to higher risk across research summaries.[3][4]

• Processed meat has strong evidence for colorectal cancer risk. [5][6]

• Fiber + plant-forward eating is one of the most reliable protective patterns. [1][7][8]

FREE Support: My 7-Day Serotonin Reset (gentle, it's free - not salesy)

If you want a simple way to eat in a calmer, more supportive pattern, especially when stress is high, I made a FREE 7-Day Serotonin Reset Plan.

It’s whole-food, plant-based, designed to support:

• steady energy

• better digestion

• calmer mood + nervous system support

👉 Download it here: CLICK LINK

Scientific Citations (Full References)

1. World Cancer Research Fund/AICR. Our Cancer Prevention Recommendations. World Cancer Research Fund website.

2. Ke J, et al. (2025). Prognostic value of C-reactive protein predicting all-cause, cardiovascular and cancer mortalities. BMJ Open, 15(8):e101532.

3. Lane MM, et al. (2024). Ultra-processed food exposure and adverse health outcomes: umbrella review of epidemiological meta-analyses. BMJ, 384:bmj-2023-077310.

4. Isaksen IM, et al. (2023). Ultra-processed food consumption and cancer risk: systematic review. Public Health Nutrition (review indexed on ScienceDirect/PubMed).

5. IARC/WHO. (2015). IARC Monographs evaluate consumption of red meat and processed meat (Press Release). 

6. World Health Organization. (2015). Q&A: Carcinogenicity of the consumption of red meat and processed meat. 

7. Ramezani F, et al. (2024). Dietary fiber intake and all-cause and cause-specific mortality (including cancer mortality): systematic review and dose-response meta-analysis. Clinical Nutrition.

8. Mayer EA, Tillisch K, Gupta A. (2015). Gut/brain axis and the microbiota. Journal of Clinical Investigation, 125(3), 926–938.

9. Keshani M, et al. (2025). Mediterranean Diet Reduces Inflammation in Adults: systematic review and meta-analysis of RCTs. Nutrition Reviews.

10. Giordano G, et al. (2024). The role of Mediterranean diet in cancer incidence and mortality. npj Aging (Nature portfolio).

11. 2025 Dietary Guidelines Advisory Committee (DGAC). (2024/2025). Dietary Patterns and Risk of Colorectal Cancer: Systematic Review (evidence through Jan 2024).