Bulletproof coffee, which has high-profile fans in Hollywood, Silicon Valley and in the sporting world, is one of the latest beverage trends to catch on here.

Popular with health nuts, it is simply black coffee with a knob of unsalted butter – similar to the kopi gu you (butter coffee) we have here – laced with a special ingredient: medium-chain triglyceride (MCT) oil.

Served in a handful of cafes and eateries here, bulletproof coffee is said to increase metabolism both in the body and the brain, thanks to the MCT oils.

Found in largest quantities in coconut oil – up to 60 per cent – MCTs can also be found in palm kernel oil, breast milk, cow and goat milk, said Dr Daniel Wai, an endocrinologist in private practice.

These fat molecules can also be found in the form of powders and oils here, like the dr. MCT range of products developed by local company Keto Science.

Unlike normal fat molecules, MCTs do not get repackaged into fat particles, then stored away in the body.

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Dr Wai said: “MCTs are not stored in the body, but are broken down to give energy directly, or changed to ketones, which is then burnt to provide energy.”

Although they give less energy compared to the animal fat we consume, they also lower the appetite and speed up metabolism, resulting in body fat reduction and weight loss.

While these fat molecules do raise good cholesterol in the body, the bad cholesterol goes up as well.

But fret not, said Dr Wai – the bad cholesterol does not increase as much as the good ones, so the overall cholesterol ratio is still favourable.

MCTs are also said to increase brain metabolism, the endocrinologist noted.

Dr Wai pointed out that MCTs have improved cognitive function and memory in people with mild cognitive impairment, Alzheimer’s disease and Type 1 diabetes patients with hypoglycemia (low blood sugar).

Toxicology studies did not find evidence of cancer potential in rats or any harmful effects in pregnant rats and baby rats.

What studies have shown is that MCTs prevented the growth of human cancer cells that were transplanted to mice, said Dr Wai.

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Due to their low smoke points, MCT oils are not recommended for frying.

Nutritionist Louisa Zhang recommended people drizzle MCT oils on food instead.

Ms Zhang, who is in private practice, said: “They are best used for beverages, dressings, desserts, sauces and off-heat cooking.

“In other words, add it in as a final ingredient after heat is turned off.”

But as with all things, these fat molecules should be taken in moderation.

Taking too much of these oils can cause stomach discomfort and diarrhoea, said Dr Wai.

He suggested starting with small amounts of MCTs, then gradually increasing the amount.

Dr Wai added: “Overconsuming MCT oils – close to 100 per cent of fat intake – is not desirable as we still need other saturated and unsaturated fats like Omega-3 and Omega-6, as well as fat-soluble vitamins.

“MCTs should not constitute more than 40 per cent of your total fat intake.”

By Foo Jie Ying, TNP. Photo: TNP File photo