'Dietary Fat: The Good, the Bad, and the Ugly' - Nutrition Guide for Physicians and Related
Looking up research on dietary fats and their effects on cholesterol, I discovered this recently published article. Here is the abstract below, and you can find the full report hosted on our website here. I will snip out some of my favorite quotations below as well.
Health professionals are often asked questions regarding fat intake:
Are all fats bad for you?
Are fats all the same?
How much is too much fat?
The objective of this chapter is to shed light on dietary fat and the controversies that surround it. The human body needs a certain amount of fat in the diet in order to survive. Each gram of fat provides 9 kcal whereas protein and carbohydrate only provide 4 kcal/g. Fat provides energy and supplies raw materials for hormones, fat-soluble vitamins, and cell membranes. Dietary fat is important for the absorption of fat-soluble vitamins (vitamins A, D, E, and K, and carotenoids) from food. Fat also helps to insulate the body against high or low temperatures and provides padding for internal organs, which protects them from shock. Fats in food contribute to taste and texture, making foods more appealing. Essential fatty acids (EFA) cannot be synthesized in the human body (liver) and must therefore be provided by diet, much like vitamins. EFA play many important roles in the body and are examined later in this chapter. Although fat is essential for survival, its consumption may be associated with obesity and coronary heart disease (CHD). These associations are discussed in more detail in Chaps. 8 and 11. The recommendation in this chapter provides a balanced, nutritious diet that includes adequate amounts of EFA as a way to help prevent obesity and chronic diseases.
Depending on their chemical structure, fatty acids can be saturated, monounsaturated, or polyunsaturated.
Some fats are called essential fatty acids and must be provided by the diet. Essential fats include n−3 fatty acids and n−6 fatty acids.
Trans-fatty acids are formed during hydrogenation of oils but are also present naturally in some foods. They increase the risk of heart disease.
Fish contains long-chain n−3 fatty acids. These fats help prevent heart disease and other chronic conditions.
Keywords: Dietary fat, Saturated fatty acids, Polyunsaturated fatty acids, n−3 fatty acids, n−6 fatty acids, Hydrogenation, Trans-fatty acids, Heart disease
Of particular note is the following statement about dietary fats: "The idea that a relatively high intake of dietary fat tends to cause excessive weight gain has been debated for several decades. Many prospective cohort studies have investigated whether the amount of fat in the diet is a predictor of weight change. These studies suggest only a weak association between dietary fat and excess weight gain. Many randomized trials have also been conducted. These have been analyzed in two systematic reviews and meta-analyses. One concluded that lowering the amount of fat in the diet leads to modest weight loss. However, the other one, which was more recent and more extensive, concluded that lowering the amount of fat in the diet does not increase weight loss. Taken as a whole, this evidence lends very little support to the view that diets with a high content of fat facilitate excess weight gain."
Also, their primary recommendation on obtaining healthy fats through eating fish: "On balance, the evidence provides strong support for the view that people should be encouraged to eat fatty fish twice a week as a means to prevent heart disease. Fish is also a source of various other nutrients including vitamin D and selenium. However, eating fish can represent a challenge for individuals who are vegan or simply don’t like fish. Fish can also be expensive and their availability on a global scale is limited by ecological limits. For these individuals, supplementation with fish oil (one or two teaspoons daily) can be the next best option, although the efficacy of this is still to be confirmed. The extent to which n−3 fatty acids from plant sources are also preventive against heart disease is also unclear."