How Many Days Of Saturated Fats Does It Take To Deplete Gut Defenses?

For dieters and athletes alike, the idea of “a cheat day” is common—a day during which one deviates from one’s normal dietary plan (specifically: where one has specific dietary rules, and chooses to break them for day).

Now, at 10almonds we don’t generally advocate for restrictive dieting as a rule, though there are some arguments to be made for it; see: What Are The “Bright Lines” Of Bright Line Eating?

For most people, a flexible dietary approach is more tenable and thus sustainable: What Flexible Dieting Really Means (And What It Doesn’t)

And it’s quite possible to take an interoceptive approach: Intuitive Eating Might Not Be What You Think

If you are in the habit of eating healthily, the idea of a “cheat day” from a diet that doesn’t feel restrictive probably isn’t an appealing prospect—because you simply don’t crave junk food; it’s not what your gut is used to.

Nevertheless, sometimes cheat days, or at least cheat meals, choose us rather than the other way around. If your social group is having a pizza night or meeting up at the burger bar, probably you’re going to be having a meal that’s not ideal.

So, what to do about that? Check out: How To Out-Cheat “Cheat Days” (Or Even Just “Cheat Meals”)

Now comes the why:

The difference that two days make

A team of researchers in Australia, namely Dr. Shanti Diwakarla et al., investigated the impact of a high-fat diet on gut health, and found that just two days of high-saturated-fat meals in mice led to reduced levels of IL-22, a key gut-protective protein.

Now, this was a mouse study, but that protein works the same for us, so it’s likely this will be reproduced in human trials (to the point that it’d be strange and surprising if it weren’t).

Why this matters: the depletion of IL-22 compromises the gut’s ability to control inflammation, even in the absence of visible symptoms like weight gain.

You may be thinking “oh, it’s good at least that it doesn’t cause weight gain”. And there are two problems with that idea:

1. This was over the course of two days. Likely weight gain would ensue if this were continued for more than two days. But more importantly…
2. The study shows how inflammation can develop silently, building up over time and potentially leading to chronic conditions years later.

Note: this is about a diet high in saturated fats, so it’s not just about junk food, it’s also relevant for the paleo diet and most iterations of the ketogenic diet.

See also:

• What’s The Real Deal With The Paleo Diet?
• Ketogenic Diet: Burning Fat Or Burning Out?

Notably, while saturated fats weaken gut defences and promote inflammation, in contrast unsaturated fats (e.g. in olive oil, nuts, and avocados) boost IL-22 production and are anti-inflammatory.

You can read the paper in full here: Acute exposure to high-fat diet impairs ILC3 functions and gut homeostasis

Want to learn more?

For gut health, a great starting point is:

Making Friends With Your Gut (You Can Thank Us Later)

…and for fighting inflammation, a great starting point is:

How to Prevent (or Reduce) Inflammation

Take care!