We often associate a stigma around the word ‘fat’ whenever we hear it. This stigma further stops people from having moderate fat diets that can, in fact, have good effects on health. Different types of fats are good and bad for our health. However, to know about them, first, we have to understand what a ‘fat’ is and how important it is for our body.
Fat is made of two parts – glycerol and fatty acids (fatty acids being the more nutritional part). Medical Science makes use of terms ‘fats’ and ‘fatty acids’ interchangeably. Fatty acids are the long hydrocarbon chains with a carboxylic acid group at one end. Every carbon atom takes four hydrogen atoms. Now, what determines the difference between fats is the number of hydrogen atoms attached to one carbon atom.
Fats are essential compounds of macronutrients present in food that our body uses to store energy. This further enables growth and functioning of cells providing energy for metabolic processes of the body. Since our bodies cannot produce fat itself, we consume it through a variety of foods.
Different fats make up for the good cholesterol (HDL) and bad cholesterol (LDL), which I am sure we all hear when we visit our doctors or watch TV ads.
Types of fats
Fats naturally exist in two categories – saturated and unsaturated fats. However, a process called hydrogenation, by chemists, has further introduced us to synthetic fat called trans fat which we have more role to play in ill health. The difference between these three lie in their chemical structure and the impacts these have on our health, which is why we use the terms good fat and bad fat.
Saturated fats: The reason why we use the term saturated for this type is that the carbon atoms in these chains remain saturated with H atoms, i.e. every carbon atoms takes up four hydrogen atoms thus forming single carbon-carbon bonds. There are no gaps in the chain, and the structure is dense and tight. These have a high melting point and are solid at room temperature. Saturated fats mostly come from meats and dairy such as:
- Animal and processed meats – lamb, fatty beef, chicken and its skin, pork, sausages, hot dogs, bacon, bologna.
- Dairy – whole milk, cream, yoghurt, butter, cheese, ice cream.
- Baked goods and snacks – pastries, cakes, biscuits.
- Plant Oil – palm oil, coconut oil, palm kernel oil.
The chemical structure of unsaturated fat is different regarding saturation of the hydrogen atoms linked with each carbon. These kinds of hydrocarbon chains form one or more double bonds in the carbon atoms (C=C bonds). These exist in a liquefied state at room temperature and are further of two types – monounsaturated fats and polyunsaturated fats.
It has only one double carbon bond in them and commonly exists in the liquid state at room temperature and solidifies at refrigeration.
It has two or more double bonds in its hydrocarbon chain making it even less saturated than monounsaturated fats. These stay liquefied at room temperature and during refrigeration. Polyunsaturated fats are further of two categories namely omega-3 fatty acids and omega-6 fatty acids.
Sources rich in unsaturated fats are:
- Fatty fish and their oil: salmon, mackerel, sardines, trout, herring.
- Nuts & seeds and their oil: walnuts, cashews, peanuts, almonds, macadamia nuts, flaxseeds
- Vegetable oil and vegetable oil-based products: olive oil, sunflower oil, un-hydrogenated soybean oil, canola oil, peanut oil, avocados, high-oleic safflower oil, corn oil, and spreads.
Trans fat is the industrialised version of unsaturated fats induced with the properties of saturated fat. Chemists use the process of hydrogenation to convert healthy oils into the solids so that they do not turn rancid. This is the worst type of fat, which is why its production and marketplace is going towards a decline.
Difference between saturated fat and unsaturated fat
Besides their chemical structure, the difference in these two fats also lies in how they treat our body. Saturated fats are widely termed to be unhealthy, but are they really? While most reading sources say so, the truth is 10% of diet constituted with saturated fats protects the liver from alcohol and toxins, thus enhancing the working of our immune system.
An amount higher than this can lead to bad cholesterol (LDL) along with lowering of the good cholesterol (HDL). Thus, saturated fats are ‘bad fats’ only if the limit exceeds than the required. The shelf life in saturated fats is usually more. Excessive consumption of saturated fats, (traditionally accused to be the mouth-watering foods) can clog the arteries and blood vessels, which causes heart attack and other blood vessel disorders.
Unsaturated fats are acceptable the ‘good fats’ known for good cholesterol. These improve liver function, reduce inflammation, and increase HDL. Although these turn rancid faster than the unsaturated fats after cooking, their health benefits are not limited.
NOTE – Where unsaturated fat makes for the ‘good fat’ and saturated fats as the said ‘bad fat’, the real culprit is trans fat which is the villain in unhealthy fat. The unnatural form of saturation introduced in trans fat is what builds up in the body leading to the damage. FDA (Foods and Drug Association) has issued a warning against trans fat which is why foods with ‘zero trans fat’ are available on market shelves. Always look for that while buying food.
Tips for healthy fat consumption
- American Heart Association recommends limiting the intake of saturated foods, which can clog arteries over the time. The RDA (Recommended Dietary Allowance) following fats is 70g of total calorie intake where 50g should be that of unsaturated fats only.
- Try replacing saturated fats with more unsaturated fats in the form of snacks and toppings in most foods. You can take nuts and seeds when you call for snack time.
- Make a habit of reading nutritional labels on the packed foods that mention the quantity of saturated, unsaturated and trans fats present.