By A new study reviewed by Dr Joseph Mercola and published on 3rd June 2025 has revealed how eating a high-fat diet can create the perfect conditions in the body for breast cancer to spread, especially in its most aggressive form — triple-negative breast cancer.
The research, conducted by the Spanish National Cancer Research Center and published in Nature Communications, showed that even short-term dietary changes could reduce these harmful effects and lower the risk of cancer spreading.
What the Study Found
Mice fed a high-fat diet (60% of daily calories from fat) had five times more cancer cells in their lungs than mice on a normal-fat diet, even when tumour sizes were the same.
The high-fat diet caused:
- Blood to become stickier by making platelets (clotting cells) overactive.
- A build-up of fibronectin, a sticky protein that helps cancer cells latch onto blood vessels.
- Blood vessels in the lungs to become leakier, making it easier for cancer cells to settle in.
In essence, the body under a high-fat diet created “pre-metastatic niches” — places where cancer cells can easily land and grow into new tumours.
How It Works
Platelets, which normally help with healing, changed behaviour on a high-fat diet. They became hyperactive, started sticking to cancer cells and vessel walls, and even acted like bodyguards, helping the cancer spread.
Fibronectin levels increased in the lungs and platelets, acting like molecular glue to help tumour cells stay in place.
Obese mice had fat tissue that released inflammatory chemicals, causing platelets to make even more fibronectin.
Reversing the Damage — It Happens Fast
Good news: Switching to a normal-fat diet for just 7 days made a big difference. It:
- Reduced platelet activity
- Lowered fibronectin levels
- Halved the number of cancer cells settling in the lungs
In real people, a simple blood test showed that women with faster blood clotting had their cancer come back 3.5 years earlier than others. This links directly to the same clotting and fibronectin activity seen in the mice.
What You Can Do to Lower Risk — Dr Mercola’s Five Tips
Dr Mercola gives five clear steps to lower cancer risk through diet:
1. Balance your food intake
Reduce fat to 30%–40% of daily calories. Eat more healthy carbohydrates like fruit, white rice and root vegetables.
2. Remove vegetable oils
Avoid oils like canola, corn, soybean, sunflower, safflower and grapeseed. These contain linoleic acid (LA), which harms cells, increases clotting and fuels cancer spread. Use grass-fed butter, ghee or tallow instead. Use olive and avocado oil sparingly.
3. Track what you eat
Use an app to see how much LA you eat daily. Aim to keep it under 5 grams — ideally under 2 grams.
4. Reduce inflammation and belly fat
Fat around the midsection increases harmful inflammation. Gentle exercise like walking and eating well-balanced meals can help reset metabolism without crash dieting.
5. Act quickly
Changes you make today can reduce the risk of cancer spreading tomorrow. Your body starts to respond within days.
Frequently Asked Questions
Q: How does a high-fat diet help cancer spread?
A: It causes stickier blood, leakier blood vessels, and more fibronectin — all of which help cancer cells travel and grow.
Q: What do platelets have to do with it?
A: On a high-fat diet, they protect cancer cells, help them stick to blood vessels and move into new organs.
Q: Can a better diet really help?
A: Yes — even a one-week switch to a better diet cut the spread in half in mice.
Q: Why are vegetable oils so bad?
A: They contain linoleic acid, which damages cells and fuels cancer-supporting processes in the body.
Q: What should I do now?
A: Cut out vegetable oils, lower your fat intake, eat healthier carbs and track your fat sources — especially LA.
Final Thought
Dr Mercola’s analysis sends a clear message: you’re not powerless. The food you eat doesn’t just change your weight — it changes the way cancer behaves in your body. Even a small shift in your diet can start turning off the signals that help cancer grow.
This study gives hope and a call to action — not just for cancer patients, but for anyone wanting to reduce their risk. What’s on your plate matters more than you think.
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