Medium-Chain Triglycerides (MCT): Coconut Oil, MCT Oil and the Trial Evidence

Medium-chain triglycerides, or MCTs, are fats whose fatty acids are shorter than those in ordinary cooking oil. The two that matter are caprylic acid, with 8 carbons, and capric acid, with 10. The single most useful figure for an Indian reader is this: coconut oil in the Indian Food Composition Tables 2017 contains only about 8 g of those two acids in every 100 g, while bottled MCT oil is made almost wholly of them. This entry in the fats section of the handbook sets out the difference and what the trials found.

What are medium-chain triglycerides?

They are triglycerides, the ordinary form of dietary fat, in which the three fatty acids attached to glycerol are of medium length. A review from the Institute of Chemical Technology, Mumbai, counts caprylic (C8), capric (C10) and lauric (C12) acid as medium-chain. Trials of MCT oil use a narrower meaning: the meta-analysis of blood lipids defines MCT oil as fat made almost exclusively of fatty acids with 6 to 10 carbons.

The length changes how the body handles the fat. According to the Mumbai review, medium-chain fatty acids released in the gut travel straight to the liver through the portal vein instead of being repackaged and sent through the lymph, and the liver burns them quickly, producing ketone bodies along the way. The same review gives MCT an energy value of 8.4 kcal per gram, a little below the 9 kcal per gram that ICMR-NIN gives for fat in general. All of these fatty acids are saturated, a point taken up in the entry on saturated fat.

Is coconut oil the same as MCT oil?

No. Coconut oil is a natural source of the raw material, and MCT oil is a manufactured concentrate. In the Indian tables, coconut oil is 49.57 per cent lauric acid and 21.12 per cent myristic acid, with caprylic acid at 2.76 per cent and capric acid at 5.18 per cent. The classical MCT oil used in a Canadian ketone study was 55 per cent C8 and 35 per cent C10. So a teaspoon of MCT oil carries roughly eleven times the C8 and C10 of a teaspoon of coconut oil.

MCT oil does not come out of a coconut ready made. The Mumbai review describes how the medium-chain acids are split from coconut or palm kernel oil and then joined to glycerol again, giving a fat that stays liquid at room temperature. The full panel for the kitchen oil is on the page for coconut oil per 100 g, and the site's coconut oil against groundnut oil comparison shows how different it is from a typical seed oil.

Coconut oil, ghee and MCT oil in Indian kitchens

Only two of the fourteen oils and fats in the Indian tables contain caprylic or capric acid, coconut oil and ghee, and neither is rich in them. The rest, from mustard to sunflower, show none at detectable levels. The table gives the share of each fatty acid, which is close to grams per 100 g of fat, and the amount in a 5 g teaspoon.

Total saturated fat is the other number to keep in view. Coconut oil is 90.86 per cent saturated and ghee 71.02 per cent in the same table, so a teaspoon of coconut oil brings about 4.5 g of saturated fat with its 0.4 g of C8 and C10. Fresh coconut in chutney or avial is a different food from the extracted oil, with fibre and water alongside the fat, as the coconut kernel values show.

How much MCT do you need under the Indian guidelines?

None. ICMR-NIN sets no requirement, allowance or upper limit for medium-chain triglycerides, and neither its Nutrient Requirements for Indians 2020 nor its Dietary Guidelines for Indians 2024 mentions them. The guidelines name only two families of fat that the body cannot make, omega-6 and omega-3. There is no deficiency of MCT, because the body does not depend on a dietary supply. The Indian documents do set limits that either oil must fit inside.

The 2024 guidelines list coconut oil, with ghee, butter, palm oil and vanaspati, among the saturated fats to limit. Two teaspoons of coconut oil already supply about 9 g of saturated fat, close to the 10 g mark. MCT oil is saturated fat as well, so a tablespoon stirred into a drink is counted against the same allowance and is not an extra on top of the cooking oil. You can set your own energy level with the calorie calculator.

Does MCT oil help with weight loss?

A little, in the trials run so far, and with caveats the authors themselves raise. A 2015 meta-analysis pooled 13 randomised trials with 749 healthy adults in which C8 and C10 replaced long-chain fats for more than three weeks. Body weight fell by 0.51 kg more with MCT and waist circumference by 1.46 cm more. The authors noted that many trials gave too little information to judge their quality, that commercial bias was detected, and that dose and duration varied.

One of the better known trials shows the scale. Forty-nine overweight adults followed a weight-loss programme for 16 weeks with either 18 to 24 g a day of MCT oil or the same amount of olive oil; 31 finished, and the MCT group ended 1.67 kg lighter than the olive oil group. Both groups attended weekly counselling. MCT oil was swapped for another oil in these studies, never added to an unchanged diet, and none of them tested coconut oil. A 2020 meta-analysis of coconut oil found no significant effect on body weight or body fat against other vegetable oils.

Does MCT oil put you into ketosis?

It raises blood ketones modestly for a few hours, which is not the same as the sustained ketosis of a ketogenic diet. In eight healthy adults eating their usual food, 30 g a day of MCT for three weeks produced ketones that peaked at 476 micromoles per litre and averaged 290 across the study day; the authors called the effect mild. A narrative review in 2018 concluded that MCTs raise ketones in a dose-dependent way, but that it is unclear whether they shorten the time taken to reach nutritional ketosis or ease the symptoms of the first days.

Coconut oil does far less. In a crossover study, nine adults took two 20 ml doses of different oils on separate days. Pure C8 was the most ketogenic, averaging 295 micromoles per litre above the control day. With coconut oil, ketones peaked at about 200 micromoles per litre above control, a quarter of the C8 peak. The wider picture is in the handbook entry on the low-carbohydrate diet and the site's Indian keto diet plan.

What does MCT oil do to cholesterol and triglycerides?

On average it leaves cholesterol alone and nudges triglycerides up. A 2021 meta-analysis of seven randomised trials found no overall change in total, LDL or HDL cholesterol with MCT oil, and a small rise in blood triglycerides of 0.14 mmol/L. The detail matters: MCT oil raised total and LDL cholesterol when the comparison oil was mainly unsaturated, and tended to lower them when it replaced longer saturated fats. The answer depends on what the MCT oil replaces.

Coconut oil has its own, larger body of trials. A 2020 meta-analysis in Circulation, covering 16 articles, found that coconut oil raised LDL cholesterol by 10.47 mg/dL and HDL cholesterol by 4.00 mg/dL compared with non-tropical vegetable oils. Switching from mustard, groundnut or sunflower oil to coconut oil in the hope of gaining MCTs therefore trades a little C8 and C10 for a measurable rise in LDL. The handbook entry on triglycerides explains the blood test.

A worked example: a spoon of coconut oil in coffee

This case is an illustration and not a real person. A 31-year-old product designer in Bengaluru reads that MCTs burn fat and starts adding one tablespoon, 15 g, of coconut oil to her morning coffee. At 884 kcal per 100 g that is about 133 kcal. Using the Indian tables, the spoon holds 1.2 g of C8 and C10 together, 7.4 g of lauric acid and 13.6 g of saturated fat. One drink has taken her past the 10 g of visible saturated fat that the 2024 guidelines count as high.

Now compare that with the weight-loss trial, which used at least 18 g a day of MCT oil. At 90 per cent C8 and C10, 18 g of MCT oil supplies about 16 g of the two acids. To get 16 g from coconut oil she would need roughly 200 g of it, close to 1,800 kcal. The trial result cannot be reached with coconut oil, and her spoon adds 133 kcal where the trials replaced one oil with another.

Side effects and who should ask a doctor first

The gut is where MCT oil causes trouble. In a dose study of 10 healthy adults given plain MCT oil with breakfast, abdominal discomfort and diarrhoea were the most common complaints, each making up 42 per cent of all side effects reported. Two side effects were recorded at the 10 g dose and eleven at 30 g, and the discomfort usually passed within 30 to 60 minutes. Blending the oil into milk as an emulsion roughly halved the number of complaints at the highest dose. The Mumbai review adds that the safe long-term intake of MCT has not been established.

Two practical points follow from the Mumbai review. MCT oil is not suited to be the only cooking oil: it smokes and foams when heated, and the authors say it should be blended with other edible oils for frying. Being made of C8 and C10, it is also not a source of the essential omega-6 and omega-3 fats that seed oils and mustard oil provide; the entry on omega-3 fatty acids covers those.

Clinical uses belong with the medical team

MCTs have a longer history in hospitals than in gyms. A ketogenic diet built partly on MCT is one of the dietary treatments studied for epilepsy that has not responded to drugs. The Cochrane review of 2020 found 13 studies with 932 participants, most of them children, and rated the evidence for every outcome as low or very low certainty; vomiting, constipation and diarrhoea were the adverse effects reported most often. Diets of this kind are prescribed and monitored by a neurologist and a clinical dietitian, and are not something to try at home or to offer a client.

Common mistakes with MCT oil and coconut oil

The second mistake is to treat MCT oil as free energy. At 8.4 kcal per gram it is almost as energy dense as any other oil, and a tablespoon in a drink is easy to overlook when you total the day. The third is to read a ketone reading after a spoon of oil as proof of fat loss. The studies above measured ketones over the few hours after the oil was swallowed; none of them measured fat loss.

A fourth mistake runs the other way: deciding that coconut is harmful and removing it from traditional food. The evidence here concerns extracted oil used as the main cooking fat or taken by the spoon; a little for tempering, within your visible fat limit, is a matter of quantity. The guide to which cooking oil suits an Indian kitchen compares the common choices.

Learning this properly

Reading a fatty acid table and weighing a trial are skills taught in NNWA's courses. NNWA, a private skill academy based in Kolkata, teaches online in English and Hindi. Its students learn to coach healthy clients and to send medical cases to a doctor; no NNWA course is a degree or a dietitian qualification. Beginners usually start with the Certification in Nutrition, while the Diploma in Nutrition, Dietetics and Public Health spends longer on fats, requirements and planning a day's food.