Keeping yourself fit and healthy, once a case of eating sensibly and exercising regularly, has become a minefield of puzzling acronyms: Hiit, IIFYM, AMRAP, WOD… One such term you may have heard on the #Fitspo grapevine is MCT oil, a fat extracted from coconut or palm kernel oil, and often added to the morning coffee of Adonis types. But what exactly is it, what does it do and what do those three little letters actually stand for? We asked the experts…

“MCT oils, or medium-chain triglycerides, are types of fat molecules that have a specific length,” says Dr Michael Newell, a lecturer in sports and exercise nutrition at the University of Westminster in London. “Think of them as a conga line with six to 12 people.” And it’s the number of units (or dancers, if you will) in the lineup that give MCTs their names – caproic acid (C6), caprylic acid (C8), capric acid (C10) and lauric acid (C12). And though they might sound scary, chances are you’ve already been eating these fats regularly, just not in their most potent form. “They are typically found as constituent parts of foods such as coconut and milk,” says Dr Newell. “When you consume the isolated form [pure MCT oil], they are quickly absorbed in the gut and transported into the blood stream, unlike longer chain fatty acids that need additional processing before they become useful.”

So, then what? “Due to their fast absorption, MCTs are sent from the gut to the liver where they convert to ketones and its these ketones that help serve as fuel,” explains Ms Kate Prince, the co-founder of Ancient + Brave, a wellness brand on a mission to “enhance brain, body and beauty”. Those who swear by the stuff, including Ms Prince, claim that an elevated level of ketones increases energy and focus, improves metabolic function and can support fat loss as part of a low-carb or ketogenic diet. “Use an MCT comprising only the key medium-chain fats C8 and C10, as these are instantly converted into ketone bodies to assist in creating nutritional ketosis. Some MCTs contain longer chain fats such as C12, which take longer for the body to convert.”

This is also where intermittent fasting comes in, “a carefully planned period of going without food followed by a period of food consumption,” Ms Prince says, and often mentioned in the same breath as MCT oils. “Ketones are essential for survival from an evolutionary perspective as when you are starving, carbohydrate stores, and therefore glucose stores, become depleted,” says Dr Newell. “The theory is simple: our body’s default source of energy is glucose, which is readily available from our recent consumption of carbohydrates,” adds Ms Prince. “But when we fast our stores are relatively depleted, so our body uses the next most accessible source of fuel, which is fat.”

Some experiments have shown that a diet rich in MCT oil reduces both body weight and waist measurement, but before you cancel your gym membership, Dr Newell suggests that the jury is still out on whether regular use will help you achieve the aforementioned Adonis-like physique. “A number of studies investigating the impact of MCT oil consumption on fat loss have been completed, but it is too early to say definitively if they are effective.” He also stresses that, as a fat, they’re high in calories and, for that reason, those with high cholesterol should steer clear. As for the brain-boosting claims? “There is some promising evidence for those suffering with cognitive impairments such as Alzheimer’s disease,” he says, but more studies are needed to determine the effect in those with normal brain function.

The most encouraging research so far concerns satiety, or feeling fuller for longer, which has been linked to weight loss. “MCTs are absorbed all in one go at the time of eating whereas longer chain triglycerides are usually absorbed in two peaks – one at the time of eating and one delayed. This might explain the observed effects on satiation [in studies],” explains Dr Jemma Day, a life sciences consultant. “Ketones are a substitute source of energy so glucose is not used up and your body could think you’ve had more food than you actually have.” This may be one explanation for why users of MCT oil report improved levels of concentration. After all, if you’re not distracted by the distant groan of stomach grumblings at your desk, you’re far more likely to actually get stuff done, right?

As for how to use it, Ms Prince explains that most people tend to add MCT oil to their morning coffee or smoothie as part of a fasting regimen, but she says there are myriad other ways to use it. “Because our True MCT Oil is odourless and tasteless, it’s incredibly versatile and you can basically add it to virtually any food to incorporate a healthy fat into your diet,” she explains, and suggests drizzling it over porridge, or using it as a substitute for olive oil in salad dressings or mayonnaise. But if you’re new to them, it’s best to take an unhurried approach to avoid any, erm, stomach upset. “We recommend starting with just one teaspoon a day and gradually increasing up to four.” Dr Newell confirms that a measured initiation is best. “Ingestion of greater than 20g [a day] can result in a rather rapid activation of your bowels,” he cautions. We have been warned.