Cutting down on fats doesn't necessarily mean it will make us healthier, because this means we will probably cut back on healthy fats as well as harmful ones.

Low fat foods, whilst lower in fat, are not always lower in calories. The extra calories are made up in added sugar and sweeteners. 

Your body needs some fat - it is a main source of energy. It helps you absorb some vitamins and minerals and is required to build cell membranes and various other vital biological structures. It is also essential for blood clotting, muscle movement, and inflammation. For long-term health, some fats are better than others. Monounsaturated and polyunsaturated fats are good fats, trans-fats are bad fats and saturated fats lie somewhere in the middle.

All fats have a similar chemical structure: a chain of carbon atoms bonded to hydrogen atoms. The length and shape of the carbon chain along with the number of hydrogen atoms bonded to the carbon chain is what makes each fat differ.

Good Fats

Healthy fats are liquid at room temperature, not solid. There are two broad categories of beneficial fats: monounsaturated and polyunsaturated fats.

Monounsaturated fats:

Good sources of monounsaturated fats are olive oil (when below 160°C), peanut oil, avocados, and most nuts, as well as sunflower oils.

Polyunsaturated fats:

Polyunsaturated fats are essential fats. That means they're required for normal body functions but your body can't make them so you must get them from food.There are two main types of polyunsaturated fats: omega-3 fatty acids and omega-6 fatty acids. 

Eating polyunsaturated fats in place of saturated fats reduces harmful LDL cholesterol and improves the cholesterol profile.

Good sources of omega-3 fatty acids include fatty fish such as salmon, mackerel, and sardines, flaxseeds, walnuts and cold-pressed rapeseed oil.

Foods rich in omega-6 fatty acids include vegetable oils such as cold-pressed rapeseed, soybean, sunflower, walnut, and corn oils.

In-between Fats

Saturated fats:

Saturated fats are fats that are solid at room temperature i.e. butter & coconut oil.

A diet rich in saturated fats can increase cholesterol levels, including LDL cholesterol (bad cholesterol), this can lead to fatty deposits in arteries and increase the risk of heart disease and strokes. Most nutritionists recommend limiting saturated fat to under 10% of calories a day.

Bad Fats

Trans-fats are the worst type of dietary fat and are a byproduct of hydrogenation. It turns healthy vegetable oils into not-so-healthy saturated fats (oils turn to solids). Eating foods rich in trans fats increases the amount of harmful LDL cholesterol in the bloodstream and reduces the amount of beneficial HDL cholesterol. Trans fats create inflammation, which is linked to heart disease, stroke, diabetes, and other chronic conditions. They contribute to insulin resistance, which increases the risk of developing type 2 diabetes.

Trans fats have no known health benefits and that there is no safe level of consumption. 

Sources of trans-fats include margarine, hydrogenated vegetable oils.