What are Unsaturated Fats?

Michael Pollick

Unsaturated fat is one of the three main types of fats, the other two being saturated fat and trans fat. These unsaturated fats are perhaps more commonly known as vegetable oils, since they are almost always plant-based, although there are some naturally unsaturated fats in certain meats. This type of fat remains in a liquid or oily state at room temperature, and is thought to be the healthiest option of the three types of fat; some examples of unsaturated fat include corn oil, olive oil, canola oil, and peanut oil. Polyunsaturated and monounsaturated fats are two types of unsaturated fat, the main difference between them being how many double bonds occur in their structure.

Bottle of olive oil with whole olives.
Bottle of olive oil with whole olives.

Saturated Fat Versus Unsaturated Fat

Unsaturated and saturated fat are essentially composed from the same raw ingredients, including carbon and hydrogen atoms. Saturated fats, such as the fat formed in animals, contain chains of carbon atoms with single bonds to hydrogen atoms; because the chain of fat contains all the hydrogen it can hold, it is considered to be fully saturated with hydrogen. The result is a solid fat product, like butter or lard, which studies have shown can lead to heart disease if eaten in excess. While it may be unwise for some people to eliminate all saturated fat from one's diet, using unsaturated fat alternatives, such as olive or canola oils, may be beneficial.

Safflower oil is an unsaturated fat.
Safflower oil is an unsaturated fat.

Unlike saturated fat, fat that is unsaturated usually contains an unstable amount of hydrogen atoms — the result is a chain of fat that is lacking hydrogen atoms. Due to the lack of hydrogen, the fat chain is generally unstable and ripe for attack from oxygen atoms, which may cause it to turn rancid. This form of fat is considered to be unsaturated, because it has not taken on all the hydrogen it can hold, and the fat will remain liquid at room temperature because of its incomplete bonding process. The liquid form is also what makes cooking oils ideal for certain recipes and cooking processes, since they do not solidify as easily as saturated fats.

Peanut oil, an unsaturated fat.
Peanut oil, an unsaturated fat.

Trans Fat Versus Unsaturated Fat

Through a process called hydrogenation, a new form of fat is formed called trans fat, or partially hydrogenated vegetable oil. Hydrogenation can occur because unsaturated fat still has room to accommodate hydrogen atoms; by bubbling pure hydrogen gas through tanks of unsaturated fats, trans fat can be made. This new form of fat combines the stability and solidity of saturated fats with the cost benefits of unsaturated fats, but is also responsible for increased plaque formation. Consumers seeking a truly healthy diet should avoid trans fats, partially hydrogenated oils, altogether and limit daily fat intake to less than 30% of the total calorie count.

Widely viewed as one of the healthiest types of cooking oil, canola oil is high in monounsaturated fats.
Widely viewed as one of the healthiest types of cooking oil, canola oil is high in monounsaturated fats.


Health experts are quick to point out the advantages of unsaturated fats over saturated or trans fats when following heart-healthy diets. The reason why unsaturated fat is considered healthier than the other types of fat is due to the nature of the fat molecules once they reach the bloodstream; saturated or trans fat molecules have a natural tendency to bond with each other on contact, which eventually leads to the formation of artery-clogging plaque. Unsaturated fat, however, contains larger molecules that tend to slide past each other in the bloodstream, which results in little to no plaque build-up; some studies have shown that unsaturated fat can help improve a person's blood cholesterol levels.

Trans fat is created when hydrogen is bubbled through oil.
Trans fat is created when hydrogen is bubbled through oil.


One major disadvantage of unsaturated fats, such as olive oil or canola oil, is that they will eventually turn rancid as oxygen molecules from the air mix with the hydrogen and carbon atoms in the fat. As a result, most commercial food producers do not use many unsaturated fats in their products. Products typically made with unsaturated fat, such as cookies or fried snacks, would only last a few days on store shelves; however, using unsaturated fat to make these same products is okay if they will be eaten within a relatively short amount of time. Also, while unsaturated fat may be considered the healthiest of the three types of fat, it is still unhealthy if eaten in excess or without other necessary nutrients.

Polyunsaturated fat and monounsaturated fat are both examples of unsaturated fat.
Polyunsaturated fat and monounsaturated fat are both examples of unsaturated fat.

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Discussion Comments


@anon6860-- A single bond full of hydrogen is saturated fat. A hydrocarbon chain with double bonds is unsaturated fat.

There is also a mono-unsaturated fat (single-double bond) and poly-unsaturated fat (multiple-double bond).

@anon72484-- There are many benefits of unsaturated fats. They are important because they help eliminate bad cholesterol and increase good cholesterol in our body. Bad cholesterol is the stuff that comes from saturated fats and clogs the arteries. If we want to prevent this, we need to consume vegetable oils.

If you want to know the benefits of fats in general, they are an important food source for our body. They also contain essential vitamins and amino acids like Omega 3 and Omega 6.

My dietitian says that fats also help increase metabolism. She says that we burn fat by eating fat. The amount of fats we consume every day should be around 40%. They're vital for health and having a fat-free diet is very bad.


I try to only consume unsaturated fats. I use olive oil for all my cooking. When I buy processed foods, I only buy ones with unsaturated fat in it. I stay away from those that have saturated fats or trans fats.

If I eat saturated fat, I feel that it will harden in my arteries, build up and eventually give me a heart attack. I'm very scared of that.


thank you so much. i needed to find the answers to 10 really hard questions and i found them all on this website!


unsaturated fats are double bonded and may contain one, two, three, or four double bonds. to answer above.

saturated fats have no double bonds.


This article links all saturated fat into the one basket which is not right. Also to link saturated fats and trans fats in the way it is done is just plain wrong. Michael Pollick should do his homework on the saturated fat coconut oil and the benefits over all the oils he mentions.


That doesn't tell how unsaturated fats are important to our body.


I was looking for some answers for my biology homework and I couldn't find chemical structure of fatty acids which wouldn't use proper chemical language. That is the first and I suppose the only site that explained to me clearly. Thank you!


mainly saturated fats are used (because they are shelf stable and don't go rancid like unsaturated fats) to create man made chemically altered fats - transfats and partially hydrogenated fats which I won't disagree are unhealthy. I can't agree that that saturated fats unaltered are unhealthy. Coconut oil are butter (both saturated fats) are healthy foods


The author articulated this concept so well. they answered my question or what these fatty acids were. thank you! wonderful job.


I wonder how the unsaturated fats are bonded or the saturated fats are too.

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