Not all oil is made equal! Oils differ based on their level of saturated/unsaturated bonds and chemical structure, flavor profile, and smoke point. Below we discuss the merits and use of different oils through examination of these properties.
There are two categories of fats: saturated and unsaturated. This distinction between the two originates in their chemical shape. Fatty acids are primarily composed of long chains of carbons with hydrogens attached. Each carbon can form four connections with other atoms.
In saturated fats, each carbon is connected to 4 different atoms, so the chain has the maximum number of hydrogens which can fit. This composition creates a linear shape, giving saturated fats the ability to pack together with other saturated fats.
In unsaturated fats, some of the carbons on the fatty acid form a double connection, known as a double bond, with an adjacent carbon. These double bonds cause the fatty acid to kink, making it more difficult for unsaturated fats to pack with other fats. In essence, these "kinks" allow for unsaturated fats to have more fluidity in the body.
LDL vs HDL
One commonly discussed difference between saturated and unsaturated fats examine the effects of these fats on cholesterol levels. Most saturated fats increase “bad” LDL cholesterol in the body while many unsaturated fats increase “good” HDL cholesterol. Thus, saturated fats are generally regarded as unhealthy fats, while unsaturated fats are labeled as healthy. The American Heart Association recommends limiting saturated fat to less than 5-6% of your daily calories, or about 13 g of saturated fat per day.
The smoke point of an oil is the temperature at which it begins to burn. At this point, a compound in the oil called glycerol converts to acrolein, an irritant and possible carcinogen found in tobacco smoke. It is important to be conscious of an oil’s smoke point so as not to heat the oil above the smoke point.
The following oils are some of our favorite choices for cooking at high temperatures. Each oil is evaluated based on saturated fat content, smoke point, and versitility in flavor.
Canola oil is a great choice for an all purpose cooking oil!
Made from rapeseed, a yellow flowering plant native to Ireland.
7% saturated fat, 62% monounsaturated fats, 31% polyunsaturated fats
Second highest in monounsaturated fat levels behind olive oil
Smoke point: 400°F
Canola oil presents a very mild flavor, so it can be used in almost any recipe.
Peanut oil is a popular choice for frying and stir frying
18% saturated fat
Smoke point: 450°F
Relatively neutral taste, with a slightly nutty after flavor
Soybean oil is a good choice if a mild flavored, high heat oil is needed.
15% saturated fat
Smoke point: 492°F.
Soybean oil accounts for 80% of commercialy-used oil in the United States!
Oil Best Used without Heat or Low Heat
The fat profiles of the following oils make them a great choice to cooking. However, the smoke points of these oils are relatively low, so it is important to be aware of how they are incorporated into a recipe.
Extra Virgin Oilve Oil
Famous for its role in the Mediterranean diet, olive oil is commonly regarded as one of the healthiest oils.
Extra virgin olive oil (EVOO) is considered to be the highest quality and have the best taste out of the many varieties of olive oil, according to food scientists.
Highest monounsaturated fat content of any oil (77%)
Smoke point of EVOO is between 320°F and 374°F, so keep the temperature low when using this fantastic healthy fat.
EVOO imparts strong flavor, so it makes a delicious base for dressings.
Flaxseed and Walnut Oil
Both flaxseed and wanut oil are geat sources of omega-3 fatty acids. (Read more about the values of omega-3s here.)
Flaxseed oil smoke point: 225°F
Walnut oil smoke point: 320°F
Great to add to salads or cooled oatmeal.
Avoid roasting and sauteeing products in these oils.
Coconut oil may be great for your hair and skin, but it is not recommended to eat! Coconut oil is 92% saturated fat. Remember - our goal is to minimize saturated fat intake.
The argument that coconut oil is healthy to consume stems from its lauric acid content. Lauric acid is a medium chain triglyceride, a type of fat. Lauric acid acts to increase the “good” HDL cholesterol in the body. However, it also causes an increase the “bad” LDL cholesterol. Many researchers believe this increase in LDL may outweigh the benefits of the increased HDL. After all, other oils (ex. olive oil) have the ability to lower HDL without the increase of LDL. At the end of the day, coconut oil is a better option than other high saturated fat choices, such as butter. However, it is recommended to choose other oils, like olive oil and canola oil, which have lower saturated fat, when given the option.
Consume Oils in Moderation
Remember to consume oils in moderation. The production of oil isolates only one component of a plant, leaving behind many other valuable nutrients. Oils are a valuable ingredient in food preparation. However whenever possible, it is advised to consume these fats in their whole plant form so as to optimize a balanced nutrient intake.
Brown, Amy C. Understanding Food: Principles and Preparation. 5th ed., Cengage Learning, 2015.