Ten best to worst cooking oils – most oils have to go through processing
Most oils sold in the market have gone through processing or what is known as purification, which strips them of nutrients, which are essential for wellbeing. To purify them, oils are treated with acid, alkali or are bleached. They are also filtered and deodorised using hexane, a solvent and cleaning agent. Oil extracted from seeds for instance has a rancid smell and, therefore they are bleached and deodorised to rid them of the offensive smells. The more it is purified, the worst it is for human health. Below is a ranking according to Happily Unprocessed survey as compiled by Rose Muthoni.
1. Extra virgin olive oil
As long as it is unrefined and not overly processed, extra virgin olive oil is the most versatile and healthy oil to cook with and eat.
It contains a large amount of monounsaturated fats and some polyunsaturated fatty acids making it a good oil for heart health.
It can be used on low to medium heat cooking because of its low smoke point as well as for baking and dressings.
2. Coconut oil
Coconut oil has a high saturated fat ratio, which has been the point of contention on whether to use it or not.
But not all saturated fats are bad for you. When cooking at very high temperatures or frying food, saturated fats are the best option because they are stable and do not smoke.
However, its use should be done in moderation. Coconut oil has been fronted as a good oil for babies who suffer from reflux because of its anti-inflammatory effects and its ability to coat the lining of the stomach to prevent corrosion for the young ones.
3. Ghee
Because it is heated for longer during its manufacturing, ghee has a stronger and nuttier flavour, as well as a darker hue.
Ghee has a higher burning point, which means it is ideal for frying or sautéing foods.
For people who are lactose intolerant, ghee is a safer dairy product because it has had many of its dairy proteins removed, thus containing lower levels of dairy proteins such as casein and lactose.
Ghee contains essential anti-inflammatory properties, which are beneficial to gut health.
4. Butter
Butter has a sublime, creamy and rich flavour that is second to none. It is the ideal oil for many cooking needs including sauce making, baking or even just spreading on bread.
Butter carries a myriad benefit for the body. It is a good source of vitamin A, a fat-soluble vitamin needed for skin health, immune function, and healthy vision.
It also contains vitamin A, which is a welcome nutrient for your heart. It is, however, advisable to use butter in moderation because it is high in calories and fat.
5. Avocado oil
Because it is unrefined just like extra virgin olive oil, avocado is a good oil for cooking. 
But because of its high smoking point, it is great for stir-frying. It is also good for cooking because it is flavourless and is creamy just like the fruit.
Although expensive, the oil has the highest monounsaturated and polyunsaturated fat contents of all cooking oils. It is also rich in vitamin E.
6. Canola Oil
Because of its high content of monounsaturated fats and a good amount of polyunsaturated fats, unprocessed canola is just what the doctor ordered.
However, it is difficult to find unprocessed canola oil. Instead, what is in the market is cold-pressed and highly processed canola oil, which means fewer nutrients overall.
7. Sunflower oil
Because of its high omega-6 fatty acids content, sunflower oil can easily cause inflammation.
Whereas the body needs omega-6 fatty acids, it needs to be balanced with omega-3 fatty acids, which are anti-inflammatory.
Sunflower oil should, therefore be consumed in moderation. However, the oil is high in vitamin E and its high smoke point and subtle flavour makes it id ideal for cooking.
8. Vegetable oils
Vegetable oils are refined and processed, thereby lacking flavour and nutrients.
These oils are pushed past their heat tolerance point and have become rancid in the processing forcing manufacturers to bleach and deodorise them to make them palatable.
Palm oil, which is an ingredient in many vegetable oils is associated with land degradation.
9. Corn oil
Although corn oil contains vitamins and phytosterols, which lowers blood cholesterol, corn oil is not a healthy fat because it is highly refined and is high in inflammatory omega-6 fats.
Human beings need to balance omega-6 and omega-3 fatty acids at a one-to-one ratio. However, consuming corn oil tips the scale in favour of omega-6 fatty acids, which can lead to heart disease, cancer, diabetes and arthritis.
10. Margarine
Margarine is a hydrogenated oil. Used mostly for spreading on bread or baking, margarine is bad for human health, banned in two European countries, but still largely in use in many nations. 
Hydrogenated oil is achieved when hydrogen gas is forced into oil and high pressure, The more solid it is, the more hydrogenated the end product.
The process of creating hydrogenated oils converts healthy fats into trans-fat. Trans-fats raise bad cholesterol levels and reduce good cholesterol levels leading to heart diseases and even death for adults.
