Fats are a useful adjunct during cooking because they supply taste and also serve as a method of transferring heat to the food. Cooking with fats and oils in controversial though because they can react differently to heating, and in turn this may impact health. Understanding cooking fats is therefore important in avoiding deleterious health consequences from their misuse, and can provide information on safer alternative that may benefit health.
Types of Fat
Fats can be saturated or unsaturated. Saturated fats are generally animal fats. Unsaturated fats in contrast are generally plant fats. Unsaturated fats are kinked molecules whereas saturated fats are straight chains. This results from a chemical double bond in unsaturated fats that causes their carbon chains to bend. The bend in the chain alters the melting point of the fat, and for this reason unsaturated vegetable fats are generally liquid and room temperature, whereas animal fats are solid.
Oxidation of Fats
Exposing a fat to heat and light can cause it to react with oxygen and go rancid. Rancid fats when consumed cause disease because they interacts with the cells of the body and disrupts normal function. To go rancid a fat must react with oxygen and for this to happen there must be a reaction site on the fat. The double bonds in unsaturated fats offer a reaction site for oxygen and this makes them far more likely to go rancid when compared to saturated fats.
Cooking with Polyunsaturated Fats
Unsaturated fats are divided into monounsaturated and polyunsaturated fats. Monounsaturated fats have one double bond, but polyunsaturated fats have more than one. This makes polyunsaturated fats far more likely to go rancid. Therefore polyunsaturated fatty acids like sunflower, rape, safflower and corn oil are poor choices for cooking. Many of these oils are also already heavily oxidised during processing, and cooking further deteriorates their quality.
Monounsaturated Cooking Fats
Because monounsaturated fats have only one double bond in their chain they are far more stable than polyunsaturated fats when exposed to light and heat. Therefore they are a far better choice for cooking. However, some monounsaturated fats are better choices than others. Macadamia nut oil contains less polyunsaturated fat than olive oil and this makes it superior for cooking because it has much less chance of going rancid.
The King of Cooking Oils
Coconut oil is a saturated oil. It is unusual for a number of reasons. Firstly, plant oils are usually unsaturated and in this respect coconut oil bucks the trend. Secondly, it is different to most saturated animal fat because it contains fats of shorter carbon chain lengths. Coconut oils is actually rich is medium chain saturated fats with chain lengths of between 8 and 12 carbons, whereas most animals fats comprise of saturated fats with long chain lengths of 18 carbons.
Cooking With Coconut Oil
Cooking with coconut oil is therefore advantageous because it provides relatively stable fats. However its high concentrations of medium chain fats are beneficial too because they have weight loss effects. In particular, medium chain fats are absorbed and passed straight to the liver where they are burnt as fuel. In this way they behave more like carbohydrates in supplying a rapid supply of energy, and in this regard are far less likely to be stored as body fat.