MCT: A Complete Guide to Medium Chain Triglycerides

Medium-chain triglycerides, also known as MCTs, 1,2,3-Propanetriol Trioctanoate, AC-1202, Capric Acid, Caprylic Acid, and Lauric Acid, are dietary fats used for increasing energy, expediting fat loss, improving athletic performance and cognitive function. ^[1] MCTs are naturally found in coconut oil, palm kernel oils, and dairy fat.

In the 1980s Dr. Vigen K. Babayan, from Harvard's University Nutrition Laboratory, devised a technique to isolate and create pure MCT oil. ^[2]

MCTs are different from long-chain triglycerides (LCTs; the most commonly consumed dietary fat in the human diet) in a number of ways. LCTs are 12 to 18 carbon atoms long and have 9 calories per gram whereas MCTs are 6 to 12 carbon atoms long and have 8.3 calories per gram. ^[2]

MCTs, compared to LCTs, are more soluble in water, smaller in size, and require fewer enzymes to break down. ^{[3] [4]} This means MCTs strain the pancreas less than LCTs and are prioritized in the digestive tract.

Your body breaks down MCTs into individual medium-chain fatty acids (MCFAs) which are a more bioavailable energy source for the body and the brain. Upon consumption, MCTs are absorbed directly from the intestine into the portal vein where they are then transported to the liver and prioritized as an energy source via beta-oxidation. ^[5] MCFAs are prioritized over LCFAs because they can enter the double mitochondrial membrane rapidly without the carnitine transport system and do not require binding to fatty-acid proteins. ^{[6] [2]}

This creates an immediately available energy source for the body and brain. As your body adapts to consistent MCT oil consumption, It creates a systemic effect by increasing fat oxidation because of the increased lipids. This equates to increased energy expenditure and fat loss.  

If you follow dietary protocols like carbohydrate backloading or the ketogenic diet, both of which emphasize high protein/low carb/high-fat phases, MCTs are an excellent non-carb or stimulant source of pre-workout energy.

MCT Benefits

17 obese female subjects consumed a eucaloric diet (re: calories burned = calories consumed) made up of 40% fat, 67% of which was either MCT oil or LCTs (via beef tallow), for 27 continuous days. Researchers found those consuming MCT oil had a 5.55% higher energy expenditure and 6.67% higher fat oxidation rate. ^[8]

A 4-week study of 19 overweight men found consuming a calorie-controlled diet high in MCTs instead of LCT-rich olive oil led to a 66% greater reduction in body weight, increased energy expenditure, and increased fat oxidation. ^[9] Interestingly those with the lowest starting bodyweights experienced the most dramatic increase in energy expenditure and fat oxidation. ^[9] This may indicate overweight men don't respond as well to the benefits of rapidly oxidizing fat sources like MCTs.

When 31 overweight males and females consumed either 18 to 24g of MCT oil or olive oil for 16 continuous weeks, those who consumed MCT oil lost 1.7 more kilograms, lost more total fat mass, trunk fat mass, and intra-abdominal fat tissue. ^[10]

These findings show replacing LCTs with MCTs will burn more fat and calories per day if you hold caloric intake constant.

One study attempted to explain how MCTs work and proposed they decrease fat mass by down-regulating two primary drivers for cell differentiation - adipogenic genes and peroxisome proliferator-activated receptor gamma. Regardless, individuals typically consume about 62.5 fewer calories per day when they eat meals contain high levels of MCTs rather than LCTs. ^[11]

Although this may not seem like a large value, over 365 days this adds up to a whopping 22,812.5 calories, or about 6.5 pounds! The type of fat you eat influences your energy expenditure, satiety, and fat burning potential.

Although research on MCTs and athletic performance is limited, mice consuming MCTs outperformed mice consuming LCTs during swimming capacity tests. ^[2] This performance discrepancy may be contributed to how the body processes MCTs more like a carbohydrate than a fat, which would increase available short term energy for aerobic activity.

Unlike some fat sources, moderate MCT consumption does not increase cholesterol and triglyceride levels in the blood. ^[11]

Some research indicates MCT consumption comprising 12 to 24% of total consumed calories may decrease fasting lipid, glucose, and diastolic blood pressure levels. ^{[6] [2] [12]} Improved lipid levels decrease the risk of serious medical conditions and improved insulin sensitivity garners a host of metabolic benefits from nutrient absorption to protein synthesis.

MCTs are considered an immunomodulator, which means they weaken or modulate immune system activity to decrease the inflammatory response. ^{[13] [14]} Other non-fitness-related benefits of MCTs include: improved seizure control, prevention of muscle breakdown in critically ill patients, reduction of tumor size, and treatment of food absorption disorders. ^[1] [15]

MCTs offer numerous benefits for both healthy and non-healthy individuals.

MCT Side Effects

The research thus far indicates MCT supplements are extremely safe to stack with other supplements and do not interact with any medications. ^[1] You can consume MCTs at any time of the day without issue.

Excessive MCT oil consumption, or any oil for that matter, can upset bowel movements. This should not cause for alarm but should suggest perhaps you're consuming too many liquid fats. The liver is the primary processor of MCTs so if you have liver problems do not use MCTs. ^[1]

MCT Supplements

The most concentrated MCT supplements are coconut oil and pure MCT oil. They are liquid, semi-solid, and capsule form. Tiger Fitness sells the following MCT supplements:

• Ambrosia Fuerte Super MCT
• NOW Foods MCT Oil
• Nutrakey MCT Oil

References