"The main fat (49%)in coconut oil is lauric acid, an antimicrobial, antifungal, and antiviral fatty acid all but unique to coconut oil and breast milk. Lauric acid kills fat-coated viruses, including HIV, measles, herpes, influenza, leukemia, hepatitis C, Epstein-Barr, and bacteria, such as Listeria, Helicobacter pylori, and strep. Monolaurin, an agent the body makes from lauric acid, fights the herpes and cytomegalovirus viruses.
The medium-chain fats in coconut oil don't need to be emulsified by bile acids before they are digested, as long-chain polyunsaturated fats do. Thus the body burns coconut oil more quickly than long-chain polyunsaturated fats like soybean oil, which it tends to store for later. For this reason, lauric acid is easy to digest, and for decades doctors have fed coconut oil to patients unable to digest polyunsaturated fats.
Medium-chain fats can also aid weight loss. Ultimately, of course, the most important thing is how much energy you consume and spend, but metabolism is more subtle than that. For example, lean protein has a higher "thermic effecct" than fat or carbs; that means it gives metabolism a boost. Lauric acid has a similar effect. A large number of studies in both animals and people show that coconut oil, when compared with polyunsaturated fats, enhances weight loss. Many people take a spoonful of coconut oil daily to aid weight loss and boost immunity.
What about heart disease? In the last thirty years, a number of studies have cleared coconut oil of any role in heart disease, and recent research confirms those findings.
Coconut oil even improves the all-important ration of HDL and LDL.
How then, did coconut oil get a bad reputation? Partly because we misunderstood cholesterol. We used to think that any fat that raised total cholesterol, as coconut oil can, was unhealthy, but we now know that total cholesterol is a poor predictor of heart disease and that raising HDL is good. Moreover, hydrogenated coconut oil was used in some studies.
Credited to Nina Planck in her book: "Real Food - what to eat and why"