It all started when people began dropping dollops of butter—instead of creamer, milk, or sugar—into their coffee. These days, fat seems to be the ‘it’ health trend—with a particular type of fat, known as MCTs, at center stage.
MCTs, or ‘medium-chain triglycerides,’ are a type of fat with a shorter molecular structure than many of the other fats we eat, says Ryan Andrews, M.A., M.S., nutrition coach at Precision Nutrition. Some of the fats with longer molecular structures, called LCTs or ‘long-chain triglycerides,’ that are common in our diets include olive oil and nuts, while the MCTs stealing the spotlight include butter and tropical oils like palm or the endlessly-popular coconut oil. “Because of their shorter length, these fats are absorbed differently in the body,” says Andrews. While LCTs go from the intestine to the lymphatic system before reaching the liver, MCTs can travel straight from the intestine to the liver because of their smaller size, says Andrews.
Cool, But Why Does That Matter?
Since MCTs hit your bloodstream faster, the body can use them as an energy source more quickly than it can use LCTs, explains Andrews. According to a review published in The Journal of Nutrition, that quick absorption suggests MCTs aren’t stored as body fat as often as LCTs are.
Also thanks to that quick absorption, some research suggests MCTs, as compared to LCTs, have a greater metabolism-boosting effect in our bodies. This metabolism-boosting process is known as ‘thermogenesis,’ in which our body uses extra energy, burning more calories, in order to process, absorb, and store the nutrients we consume. Case in point: A study published in the American Journal of Clinical Nutrition found that men who ate a meal including MCTs (30 grams, to be exact) burned more calories throughout the following six hours than men who ate a meal including a similar amount of LCTs (38 grams).
Researchers also suggest that since MCTs are absorbed more rapidly, they make us feel satiated faster, which can help reduce how many calories we end up eating, according to that Journal of Nutrition review. That effect may even influence weight loss over time, according to a study out of Columbia University. In the study, overweight adults consumed 12 percent of their daily calories from either MCT oil or olive oil (an LCT) for 16 weeks. The MCT oil group lost more body fat, specifically around their midsections, than team olive oil. Though we already know that the amount of fat we consume can affect our total caloric intake and body weight, this research suggests that the source of that fat makes a difference, too.
Related: The Truth About Belly Fat
What’s The Catch?
Before you start smothering everything in coconut oil or butter, keep in mind that as intriguing as MCTs sound, they still pack as many calories per gram as all fats—and too much can still have a negative impact on your body, says Andrews.
While many LCTs are unsaturated fats that support cholesterol and heart health (like omega-3s, for example), MCTs are saturated fats—and the jury is still out on their long-term impact on health, according to the Harvard School of Public Health (HSPH). There’s been some back-and-forth on saturated fat recently, with some research questioning just how much they impact our risk of chronic disease, but the HSPH still suggests that consuming unsaturated fats like nuts, seeds, and their oils can better support heart health over time. It’s totally fine to cook with coconut oil or butter sometimes, just don’t go out of your way to make them staples in your daily diet, says Andrews.
But what about those weight-loss perks? When it comes to reaching or maintaining a healthy body weight, your nutritional foundation is much more important than whether or not you add MCT oil to your smoothie, Andrews says. If you’re putting butter and coconut oil in your morning coffee but then downing a bagel and a glass of OJ for lunch every day, those MCTs aren’t going to be a weight-loss magic bullet, he says.
A dietitian can evaluate the bigger picture of your diet and help you establish a balanced nutrition plan that will support your weight-loss goals. And, yes, MCTs can be a part of that plan. “There’s a level of individuality to nutrition, so I encourage people to experiment and see how they feel,” says Andrews. If you’re interested in hopping on the MCT trend, talk to your dietitian about how to incorporate them in a healthy, weight loss-friendly way.
Related: Check out our buzziest MCT oils.