Monounsaturated fatty acids (MUFA) are good for your health "as long" as you don't cook with them.
MUFAs are fatty acid molecules that are missing a pair of hydrogen atoms in their carbon chain. Please visit types of fats for a better understanding of fats, its carbon chain, etc.
Olive oil is widely considered the best monounsaturated fat. It is a major contributing factor to the health benefits of the Mediterranean diet.
But because its MUFA's carbon chain is missing a pair of hydrogen atoms, olive oil and other monounsaturated fats are highly susceptible to oxidation. Simply put, they get rancid easily! For this reason, dietary fats mainly composed of MUFAs should not be used for cooking.
When it comes to cooking, saturated fatty acids (SaFA) predominant in coconut oil are far superior to MUFAs. SaFAs don't have missing pairs of hydrogen atoms in their chain, making them very stable under most cooking temperatures.
MUFAs plentifully found in peanut and olive oils are vulnerable to spoilage. In contrast, 92 percent saturated coconut oil is ultra resistant to oxidative damage and free-radical formation. Coconut oil is so stable that when heated, it is 12 times more resistant to oxidation than canola oil, another monounsaturated fat.
Coconut oil, if naturally processed, can easily stay fresh for at least three years, without refrigeration. My uncle had a bottle full of homemade virgin coconut oil he forgot he had. After stumbling upon it twelve years later, the oil was STILL fit for human consumption. Now, that's tough!