A guide to good and bad fats

Saturated and unsaturated fats have very relevant nutritional differences. Do you know what they are? Discover the fat types, their functions, and possible benefits with the help of some examples.

Why are fats useful?

Fat is the richest source of dietary energy available in the diet. If it is consumed in excess, it produces an energy intake that is too high. If this energy is not used, it will cause overweight and obesity, favouring the appearance of cardiovascular diseases. However, fat is also involved in other functions of our body:

-   Keeping our skin and hair healthy.

-   Helping to absorb fat-soluble vitamins (A, D, E and K).

-   Insulating our body, which helps to keep us warm. 

Dietary fats are composed of building blocks called fatty acids. The structure of these determines the health effects of a certain type of fat. Whilst some fatty acids are essential components of the diet, others can harm our health. As with most nutrients, recommendations exist to help establish a good dietary balance.

What are the different fat types?

Fats can be classified into different groups depending on the type of bonds they have in the fatty acid chain, so how much of each type of fatty acid they contain.

Saturated fats

Saturated fats raise both high-density lipoprotein (HDL) levels - or "good" cholesterol - and low-density lipoprotein (LDL) - or "bad" cholesterol - levels. This may increase the risk of cardiovascular diseases and other major health problems. Foods containing this type of fat should not be removed from the diet but included in moderation. Examples of foods which are a source of saturated fats include fatty meats and dairy products, such as butter, cheese, whole milk, cream, and ice cream. Some vegetable oils, such as coconut, palm and palm kernel oil also contain saturated fats.

Trans fats

Trans fats, also called trans-unsaturated fatty acids or trans-fatty acids, are more harmful since they have a double effect: not only do they increase LDL (the “bad”) cholesterol levels, but they also reduce the HDL (the “good”) cholesterol levels. Trans fats are found in foods industrially made with vegetable oils and are found in snacks and salty snacks such as potato chips, sticks, cookies, pizzas, margarine, cereal bars or hamburgers. These fats should be avoided.

Unsaturated fats

Unsaturated fats are considered to be beneficial since they can improve blood cholesterol levels, ease inflammation, stabilize heart rhythms, and play several other beneficial roles. There are two types of “good” unsaturated fats:

• Monounsaturated fats which are found in high concentrations in olives, avocados, nuts (such as almonds, hazelnuts, and pecans) and seeds (such as pumpkin and sesame).
• Polyunsaturated fats can be found in high concentrations in sunflower, soybean, and flaxseed oils, walnuts, flax seeds and fatty fish. Among these kinds of fats, Omega-3 Polyunsaturated fatty acids are considered essential for humans. Some of the health benefits related to these fatty acids are the prevention of macular degeneration, cardiovascular diseases, age-related mental decline and degenerative diseases such as Alzheimer’s and Parkinson’s diseases. They also seem important for pregnant people due to the positive effect on the visual and cognitive development of the baby.

Distinguishing fat types and their benefits are essential to follow a healthy diet. It’s important to recognise that not all fats are bad, and eating some of them in the right quantities can be beneficial – and even essential – to the correct functioning of our bodies. 

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