Nick NorwitzMD PhD, Oxford-Harvard | Metabolic Health Educator | “Stay Curious”

Saturated Fats: Not All Are the Same

20 Jul 2025 · 2 min

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1:30

In this educational monologue, the speaker critiques the common practice of lumping all saturated fats together as harmful, arguing that such oversimplification ignores important biochemical differences. Using analogies, the speaker explains that medium-chain triglycerides (MCTs) are metabolized uniquely: they travel directly to the liver via the portal vein and bypass the carnitine shuttle required for longer-chain fatty acids, giving them distinct metabolic effects. The talk then shifts to long-chain saturated fats, highlighting stearic acid (C18) as an example that promotes mitochondrial fusion, does not raise LDL cholesterol like palmitic acid (C16), and may possess anti‑cancer properties, including against colon cancer. The overall message is that saturated fats are a heterogeneous group, and their health impacts must be evaluated individually rather than as a single class.

Chapters

Saturated fat oversimplified. In the existing studies, saturated fats are lumped together as a single entity. Lumping saturated fats as a single article and labeling them as dangerous is the same as lumping all felines into a group and calling them dangerous. Even though a tiger could rip your head off with a swipe of its paw, and a kitty is only dangerous insofar as its cuteness factor could be off the scale. Different saturated fats have different effects on metabolic health. Medium-chain triglycerides, or MCTs for short. You've probably seen them in keto circles as Bulletproof Coffee. MCTs are processed in a way that is distinct from their longer chain cousins. Rather than being taken up into the lymphatic system and circulated in chylomicrons, MCTs go directly via the portal vein to the liver, more like a protein or a carbohydrate in digestion than long chain fats. Additionally, MCTs can circumvent the normal carnitine shuttle system that longer chain fatty acids need to get into mitochondria to be burned for fuel. The specifics here aren't critical. The point is MCTs have a distinct metabolism. Different saturated fats are different. Stearic acid— this is C18. The examples of the biological differences of saturated fats just don't stop. Even among long-chain saturated fats, there are diverse metabolic impacts. For example, stearic acid, C18, has been shown to promote mitochondrial fusion, enhancing metabolism, does not increase LDL cholesterol like C16, and may even fight various forms of cancer, including colon cancer.