TLDR Summary:

Medium Chain Triglycerides (MCT) are fat molecules containing one of four different medium chain fatty acids (MCFA). Unlike most fats, MCTs are absorbed quickly and MCFAs are able to be metabolized directly by the brain and nervous system. They are metabolized rapidly in the liver, creating an influx of ketones in the process. The combination of rapid absorption, access to the brain/nerves, and nearly instantaneous ketone production makes MCTs the ideal fuel. Like all fats, they keep blood sugar/insulin low and control hunger, but provide instant energy that can be used by the entire body like a carbohydrate.

MCTs are digested quickly like carbohydrate and their MCFAs are available for use by brain/nerve cells. You also create ketones from MCFAs much quicker than from other fats. The MCFAs and ketones combine to provide quick, sustained energy, and their fast metabolism allows you to generate ketones even with slightly higher carbohydrate intake.

MCTs are found in coconut oil (62%), palm kernel oil (50%), full-fat dairy (10%), and MCT oils & powder (~100%).

MCTs Long-term benefits:

Helps fat loss by boosting metabolism and satisfying your appetite
Improves cognitive function and memory by generating ketones which feed and “protect” neurons. Helps treat epilepsy or neurodegenerative diseases like Alzheimer’s.
Fights infections due to antibacterial, antiviral, and antifungal properties.
Improves nutrient absorption (vitamins, minerals, etc) from other foods. Helpful for those with gut disorders like Crohn’s and leaky gut.
Reduces cardiovascular disease risk by helping control weight, raising HDL cholesterol, and lowering inflammation.

The only downside is the potential for “disaster pants” if you consume too much at one, you’ll be running to the bathroom, but this goes away with tolerance.

What Are They?

Triglycerides are the food and storage form of fat. Each triglyceride contains a glycerol molecule and three fatty acid chains, each containing any number of carbon molecules (usually an even number). The number of carbons determines the length of the fatty acid chain, and we categorize them as:

Short Chain: 2-6 carbons
Medium Chain: 8-12 carbons
Long Chain 14-18 carbons
Very-Long Chain: 20+ carbons

Medium Chain Triglycerides (MCT) contain fatty acids with anywhere from 8-12 carbons. Specifically, the medium chain fatty acids (MCFA) are (The “C” stands for carbon and the “0” means it’s saturated):

Caproic Acid (C6:0) - fastest metabolism but only small amounts in food
Caprylic Acid (C8:0) - very ketogenic, very fast metabolism in brain
Capric Acid (C10:0) - slightly less ketogenic and a little slower metabolism in brain
Lauric Acid* (C12:0) - digests slower like LCFAs, not metabolized in brain*, most antimicrobial

* Technically, lauric acid has a medium-length chain, because that’s how chemist categorized it. However, it’s metabolized like a long-chain fatty acid.

Why Size Matters

Most fats in our diets are of the long or very-long chain variety. What this means is that they take much longer to digest, since they require an extra enzyme in order to be absorbed through the intestines. It also means they cannot be directly utilized by your brain and nervous system. Normally, no big deal; as a ketogenic eater, you already have a steady supply of fatty acids being released into the blood from body fat. You also know from "How Food Works" that even long chain fatty acids are metabolized through beta-oxidation, and that beta-oxidation in the liver creates ketones that can be taken up by your thirsty brain.

It may seem terrifying, but we all leave ketosis from time to time, maybe due to a cheat or a little too much protein. MCTs can get you back faster. Or perhaps you’re starting your day or about to do some heavy mental lifting and want a quick boost of energy, but you want it sustainable and without the crash than comes with eating carbohydrates. MCTs are the perfect fuel for these situations. They might just be the perfect fuel, period. The Ryan Gosling of foods.

Which Foods contain MCTs?

The most common source of MCTs is in coconut oil, although only about 15% of the fats are “fast acting ” MCTs of C6 Caproic, C8 caprylic and C10 capric acid. Other sources of MCTs are as follows (1, 2, 3):

Coconut oil - C6: <1% C8: 7% C10: 8% C12: 48%; 62% total MCFA

Palm kernel oil - C6: <1% C8: 3% C10: 5% C12: 46%; 54% total MCFA

Full-fat dairy - C6: 2% C8: 2% C10: 3% C12: 3%; 10% total MCFA

MCT oil / powder ratios vary by product; 100% total MCFA

Coconut and dairy (especially grass-fed) contain decent amounts of MCTs, but by far the easiest way to get a big dose is by taking them in an oil or powder. They are minimally processed and make great additions to coffee, baked goods, and dressings.

What’s Unique About MCTs?

Due to their shorter chains, MCTs are not only rapidly absorbed through your intestines and directly into the bloodstream, but unlike most fats, can cross the blood brain barrier and fuel your brain cells with a quick, yet long lasting energy source. Also, the shorter the chain, the quicker a fatty acid can be oxidized, and the quicker it produces ketones. And like all fats, since there’s no insulin released, there’s no blood sugar crash afterwards. This makes MCTs the perfect breakfast food (i.g., keto or bulletproof coffee), and great before anything where you want to feel on fire (in a good way).

MCTs/MCFAs are as strong, clean and efficient a fuel as you can get your paws on.

Lauric acid is technically a medium chain fatty acid. However, it acts just like a long-chain fatty acid in that it can’t be directly absorbed through the intestine and can’t cross the blood brain barrier. For this reason, some people don't consider lauric acid to be a MCFA. Although it has it’s own sexy qualities (its the most antimicrobial), lauric acid does not provide the fast digestion and quick energy of the other MCFAs.

What are the Long-Term Benefits?

Besides giving you quick, sustained energy, MCTs have the potential to help you:

Improve cognitive function and memory
Lose fat or maintain weight
Fight bacteria, viruses, and fungi
Improve digestion and nutrient absorption
Improve heart health

Cognitive Function and Memory

Because of their ability to rapidly reach your brain both directly and through fast conversion to ketones, MCTs can improve cognitive function and memory (4, 5, 6, 7). It’s known that ketones activate special proteins that repair and protect brain and nerve cells. This characteristic is extremely beneficial to those suffering from loss of neurons due to aging or neurodegenerative diseases like Alzheimer’s disease. This study on Alzheimer’s treatments noted, “In small scale human trials, MCT supplementation boosted cognition in individuals with cognitive impairment and mild forms of Alzheimer's disease after just a single dose." (8) Ketones are also known to reduce the symptoms of epilepsy (9).

Body weight and body fat

This site is centered around the idea that a high-fat, low-carb diet will help you lose fat through the removal of high amounts of glucose and insulin and the appetite-suppressing effects of high fat intake, and MCTs use these mechanisms just like any other fat source. In addition, there’s even some research showing that MCTs may have even more fat-burning properties than long-chain fats by slightly increasing the amount of energy expended with the same amount of calorie intake (10, 11, 12, 13, 14, 15, 16, 17, 18). This makes MCTs a powerful weapon in the fight against all the things we are trying to destroy - insulin resistance, Type-II diabetes, metabolic syndrome, obesity, heart disease, and cancer. And because MCTs produce ketones so readily, this may enable you to enjoy some of the other benefits of ketone production, even while eating slightly more carbohydrates. You can’t eat an entire fruitcake, but maybe an extra 25 carbohydrates a day (this is highly individual).

Antimicrobial effects

MCTs/MCFAs act as a natural antibiotic, antiviral, and antifungal by coating the surface of these microbes and killing them (19, 20). It’s been shown to be especially effective against candida and yeast infections (21, 22, 23). It’s also known to kill:

staphylococcus (causes food poisoning and UTIs)
streptococcus (causes strep throat, pneumonia and sinus infections)
neisseria (causes meningitis, gonorrhea and pelvic inflammatory disease)

Most of this antimicrobial effect comes from the lauric acid (C12). Lauric acid is prevalent in coconut oil, but many MCT products are made without it, since it takes longer to digest.

Digestion and Nutrient absorption

The aforementioned antimicrobial effects of MCTs have the added benefit of aiding digestion, because they kill a lot of the bacteria that cause digestive issues. This could help those suffering from leaky gut, Crohn’s disease, and gallbladder infections. In addition, fats are required to absorb certain vitamins like A, D, E, and K, and minerals like calcium, magnesium, and phosphorus. Eating all the plants in the world will not allow you to fully absorb the nutrients they contain without the addition of fats.

Heart health

MCTs are saturated fats. Generally speaking, saturated fats can raise the total level of cholesterol in your blood, particularly raising HDL cholesterol. We now know that total cholesterol is not associated with risk of heart disease (24), and HDL cholesterol protects against heart disease (25). We also know that the true root cause of heart disease is inflammation. MCTs have been shown to have anti-inflammatory properties (26, 27). When you consider its effects on weight loss, MCT’s ability to raise HDL and lower inflammation means that it could help prevent heart disease.

What are the Downsides?

Not much. The only common issue with MCTs are their tendency to cause disaster pants when you take too much at once. However, this is easy to rectify - simply take a ½ dose and see how you feel, then gradually increase the dose over the course of 2 weeks until you build up a tolerance. Some people (especially if you have been keto for a while) have no issues with a full dose or more right off the bat. As you get used to them your digestive tract gets more efficient at absorbing them.

So, now you understand what MCTs and MCFAs are, where they are found, how they work and what they are good for.

As far as I’m concerned, there aren’t many nutrients as important as MCTs. It’s got both immediate and long-term benefits with very little downside. Lucky for us, there market is exploding with new oils and powders, and there are many quality products to choose from. In my next article we'll give you a look at the different MCT products to help navigate these choices.

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