Don’t believe ads that say coconut oil is healthful because it contains medium chain triglycerides that can raise the good HDL cholesterol a little bit. Medium chain triglycerides are only a small part of the fat in coconut oil. Ninety-two percent of the fat in coconut oil is saturated, which is 50 percent more saturated fat than is in butter, and is far higher than levels in olive, canola and other plant-based oils. Saturated fats can raise blood levels of the bad LDL cholesterol (BMJ, 2015;351:h3978).
A study of 60 mice found that eating small amounts of coconut oil for eight weeks reduced their ability to make insulin and leptin, which would increase risk for obesity and diabetes (Journal of Functional Foods, July 2023;106:105600). Insulin drives sugar into cells. When you are insulin resistant, sugar loses some of its ability to enter cells and is converted to fatty triglycerides that make you fat. Leptin acts on the brain to decrease hunger, and lack of leptin makes you hungry so you eat more. The mice developed markers of harmful inflammation, significant fat weight gain and decreased energy production. A review of 17 studies in humans found that coconut oil does not help a person to lose weight, lower blood sugar levels, or dampen down harmful inflammation (Circulation, Jan 13, 2020;141:803–814). Coconut oil increased LDL cholesterol much more than soybean, olive, safflower or canola oils. Another review found that replacing coconut oil with unsaturated fats reduced blood risk factors for heart attacks (Nutrition Reviews, Apr, 2016;74(4):267–280).
Questionable Coconut Oil Benefits
Promoters of coconut oil often cite studies showing that people in societies that eat a lot of coconut oil are not at increased risk for heart attacks (Asia Pac J Clin Nutr, 2011;20(2):190–95). However, these societies do not eat the heart-attack-provoking “Western Diet.” They eat the flesh, milk and water of coconuts and freshly-extracted oil rather than commercially processed coconut oil. They also eat a lot of other plants and seafood, and do not eat much mammal meat, processed meats or sugar-added processed foods.
Some of the fat in coconut oil is medium chain triglyceride fatty acids (MCFAs) that have been reported to be different from shorter and longer chain fats because they appear to raise blood levels of the harmful LDL cholesterol less than the saturated fat components (J Am Coll Nutr, Oct 2008;27(5):547–552). However, other studies show that MCFAs in coconut oil raise LDL cholesterol more than other plant oils such as palm oils (Am J Clin Nutr, 1997;65:41–45). A review of eight papers found that medium chain triglycerides in coconut oil did not behave differently from saturated fats to reduce LDL cholesterol (Cureus, Apr, 2022;14(4):e24212). Most of the studies show that coconut oils do raise blood levels of the harmful LDL cholesterol (JAMA, published online April 8, 2020), and that substituting polyunsaturated fats for the saturated fats in coconut oils reduces blood levels of the harmful LDL cholesterol (Br J Nutr, 2001;85(5):583–90).
One study showed that coconut oil raises blood levels of the healthful HDL cholesterol by 4 mg/dL (Evid Based Complement Alternat Med, 2017;2017:7251562), but several other studies suggest that raising HDL cholesterol does not prevent heart attacks. One study of more than 100,000 patients showed that raising HDL cholesterol does not reduce heart attack risk (BMJ, 2014;349:g4379) and another study showed that people with genetically high HDL cholesterol are not at reduced risk for heart attacks (Lancet, 2012;380:572–580).
I think you should ignore claims of special health benefits from coconut oil. Reasonable amounts of coconut oils appear to be neither harmful nor healthful. Your total diet is far more important than whether you eat or restrict coconut oils. Whatever vegetable oils you choose, they should be a very minor part of your diet, limited to a few tablespoons a day. Preventing heart attacks involves following an overall heart-healthy diet that includes a wide variety of plants and restricts mammal meat, processed meats, fried foods, sugar-added foods and all sugared drinks including fruit juices.
Coconut oil has a low smoke point of 350°F, so it definitely should not be used for deep frying. I believe that everyone should limit deep-fried foods (foods cooked by submerging in vegetable oil at high temperatures). Deep frying forms cancer-causing nitrosamines (J Food Sci, May 2012;77(5):C560-5). If you must deep-fry a food, choose an oil with a high smoke point, such as avocado, sunflower seed or peanut oil. Coconut oil and other low-smoke-point oils such as olive oil can be used for brief sauteing of moist foods such as onions, green peppers, garlic and celery, or stir-frying combinations of food that include plenty of vegetables. They can also be used uncooked for salad dressings, dips and sauces, or in recipes with a high water content such as soups. See my Guide to Vegetable Oils.