If meat causes cancer…

Disclaimer: I’m meat-cancer agnostic.  *IF* meat causes cancer (and I don’t think it does), it happens extremely slowly and only at very high levels of intake: to get statistically significant risk ratios, researchers usually look to top vs. bottom quartiles, which is quite a large difference in intake.

Meat-cancer studies Tl;dr: some studies show positive associations, some neutral, and none are negative (ie, it’s unlikely meat prevents cancer).

That said, if meat does cause cancer, here is how it might happen:

1. The “Maybes:” AGEs, leucine/mTOR, methionine, etc., but only in combination with numbers 2 & 3.  Not by themselves.

2. Circadian arrhythmia and cancer: potential mechanisms

3. Most animal foods have a lot of linoleate 18:2n6 or at least a lot more n6 than n3 (grass-fed is usually a little better in this context).  More on this below.




One aspect of circadian arrhythmia manifests as low or mistimed melatonin.

This is one of the most compelling studies on the melatonin/cancer link, imo (also discussed HERE): Melatonin-depleted blood from premenopausal women exposed to light at night stimulates growth of human breast cancer xenografts in nude rats (Blask et al., 2005)



Melatonin inhibits tumor linoleate uptake, but you need a high peak for this to happen.  Artificial light at night prevents this.

Many cell types proliferate at night; ideally, tumors would love a low melatonin high linoleate milieu at night.  And maybe an abundance of those things listed in #1 above.


What’s up with the linoleate, you ask?


Tumors turn linoleate into 13-HODE, a potent mitogen (Dauchy et al., 2015).




By this logic, vege oils should be worse than meat (they probably are), depending on the importance of the factors listed in #1.

-In any case, replacing some steak with seafood may be prudent.

-No artificial light at night.

-I don’t know if melatonin supps will work in this #context, but doubt they’d hurt.

-By preserving endogenous melatonin production, blue blockers should definitely help.

-Same goes for an earlier eating pattern and sunlight in the morning (or at least some bright light).


Linoleate… sheesh


calories proper


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  • Conventional egg yolks and poultry skin are very n6-rich.

    “Greater consumption of eggs and poultry with skin was associated with 2-fold increases in risk in a comparison of extreme quantiles: eggs [HR: 2.02; 95% CI: 1.10, 3.72; P for trend = 0.05] and poultry with skin (HR: 2.26; 95% CI: 1.36, 3.76; P for trend = 0.003).”

    “Our results suggest that the postdiagnostic consumption of processed or unprocessed red meat, fish, or skinless poultry is not associated with prostate cancer recurrence or progression, whereas consumption of eggs and poultry with skin may increase the risk.”


  • Man

    n-6 … n-6 … what about nuts and seeds ? 😉

    • I’m sure if you’re getting enough n3’s & seafood, a few nuts & seeds won’t hurt you 🙂

  • Sam


    What are your thoughts on Olive/avo oils? They are high in oleic acid and it seems oleic acid feeds cancer.

    It is clear that one needs to increase Omega 3 fatty acids
    whether from plant or animal sources. I’m not clear about other fatty acids, their sources and their impact on cancers and and cardiovascular system. Would you please shed some light which is the most current and accurate research in regards to them ?

    For example, some sources caution and warn about oleic fatty acid and its relation to growth of cancers. Such sources advice to lower consumption of olive oil (and it seems avocado is about 70-80% oleic acid).



    From the other perspective, many people are switching to lard, butter and coconut oils, but these sources are high in saturated fats, what about cardiovascular risks and published links to cancers too?

    • interesting… thanks. I remain skeptical of any potential cancer &/or CVD promoting effects of olive, avo, and SFA-rich oils

  • BullB Man

    As one does calisthenics, consuming 300g of fat everyday (along with 150g protein and some vegi+cocoa) would almost inevitably get me more than 20g or n6 (unless I just eat pure tallow/butter/coconut oil all day long, btw coconut oil give me bad stomach times and Idk why). Though I eat like a big can of sardine (around 5g of n3 in it) almost everyday, I still do not feel safe doing this long term. What would be your thoughts on this Dr?