The role of saturated fat in health has been distorted from the original observations within the scientific literature. Saturated fat has been implicated as a disease causing agent, and this is really at odds with the data from peer review journals. The reason for this ambiguity regarding saturated fat is that interpretation of data can be biased by changing the perspective of the interpreter, and preconceived bias in viewpoint plays a role in this distortion. Dietary saturated fat has been suggested to play a role in the aetiology of cardiovascular disease, with this viewpoint based on supposed science. However, this viewpoint is based on a particular interpretations of particular small aspects of science, and it is often overlooked that much data has to be ignored in order for this viewpoint to remain legitimate. Therefore taking the science as a whole into account we can say that the hypothesis that saturated fat is a disease causing agent has been falsified experimentally, and is therefore not valid.
The ideas that restriction of saturated fat in the diet is beneficial at protecting from cardiovascular disease, or that excess saturated fat in the diet is able to cause cardiovascular disease has not been demonstrated. In fact, populations such as the Maasai that consume very high saturated fat diets have an absence of cardiovascular disease, while studies that have restricted saturated fat have not been able to prevent the worsening of the condition, unless other dietary variables are changed. Much of the propaganda surrounding saturated fat comes from the large corporations that have a vested interest in selling food, and in this regard they use the mainstream media as a conduit to peddle their lies and spin. Of course one of the main problems with claiming saturated fat consumption results in poor health outcomes is the fact that saturated fat is a diverse range of chemicals with very different biological effects and grouping all saturated fat together in one category does a disservice to common sense and logic.
Likewise, the idea that polyunsaturated fats are healthy fats is misguided because polyunsaturated fats are a large heterogenous group of chemicals that can have quite different effects on animals. To say that all of these fats are healthy is not only misguided, it is also based on no scientific data. In addition, the idea that one group of fats can be healthy or unhealthy does not take into account that such fats can be altered chemically and thus their physical and chemical properties changed. The oxidation of fats for example changes the metabolic fate of polyunsaturated fats in human nutrition. Only two polyunsaturated fatty acids are essential to health, and beyond these two fats, there is no evidence that polyunsaturated fatty acid have any beneficial effects on health, unless other dietary variables are also manipulated. The vilification of eggs as cardiovascular disease causing agents is also disingenuous because while they are high in cholesterol they can also be high in polyunsaturated and essential fatty acids.
Confusion also surround studies that have attempted to control the diets of subjects. For example, some studies have claimed that lowering saturated fatty acid levels in the diet while concomitantly increasing polyunsaturated fatty acid levels has health benefits. But is it the lowering of saturated fats, or the raising of polyunsaturated fats, or some other variable that is the cause of these changes? With regard the latter, the control of a single variable in a diet of a free living human is virtually impossible and so it is never exactly clear what is having the effect. For example polyunsaturated fats contain plant sterols that constitute a significant quantity of the lipids in polyunsaturated fats. These phytonutrients have been shown to lower plasma cholesterol levels and so it is difficult to attribute any effects of polyunsaturated fats to the fatty acid they contain. Likewise, low saturated fat diets are also high fibre diets and as such the attribution of the cause of any changes to cardiovascular risk is not possible.