Fats are also called ‘fatty acids’ or ‘lipids.’ Fats in our body are made up of three molecules joined together. These three-molecule are carbon, hydrogen, and oxygen.1
Most of the fat we need is made by our bodies, but there are some fats our bodies cannot make. We can only get these fats by eating them. These fats are called “essential” fats because it is essential that we get them from food. Essential fats include Omega-3 fats (found in foods such as fish and flax seed) and Omega-6 fats (found in foods such as nuts, seeds, and corn oil).
Fat has 9 calories per gram, more than 2 times the number of calories in carbohydrates and protein, which each have 4 calories per gram.2
Why is fat important?
Getting enough fat in your diet is important for staying healthy.
We need fat because:
- Fat helps absorb vitamins, like vitamins A, D, E, and K
- fat keeps our skin healthy.
- Essential fats like Omega-3 are important for heart health.
- Healthy fats, like unsaturated fats from plant oils, can help lower levels of LDL (lousy) cholesterol.
- Fat adds flavour to food.
- Fat keeps you feeling satisfied longer after a meal.3
- The fats you eat give your body energy that it needs to work properly. During exercise, your body uses calories from carbohydrates you have eaten. But after 20 minutes, exercise depends partially on calories from fat to keep you going.4
- Fats help the body to produce and regulate hormones5
- Fats also play important functional roles in sustaining nerve impulse transmission, memory storage, and tissue structure.
There are three main types of fat in the foods you eat:
- Unsaturated fats from plant foods.
- Saturated fats from animal foods.
- Trans fats from commercially prepared, processed foods.3
Unsaturated fats
Unsaturated fats, which are liquid at room temperature, are considered beneficial fats because they can improve blood cholesterol levels, ease inflammation, stabilize heart rhythms, and play a number of other beneficial roles.6
There are two kinds of unsaturated fats:7
- Monounsaturated fats are found in avocados and peanut butter; nuts like almonds, hazelnuts, cashews, and pecans; and seeds, such as pumpkin, sesame, and sunflower seeds. It is also in plant oils, such as olive, peanut, safflower, and sesame oil.
- Polyunsaturated fats include omega-3 fatty acids and omega-6 fatty acids. Polyunsaturated fats are found in plant-based oils like soybean, corn, and safflower oils, and they’re abundant in walnuts, flaxseeds, sunflower seeds, and fish like salmon, mackerel, herring, tuna, and trout.
Saturated fats
Saturated fats are solid at room temperature and are sometimes called solid fats. The basic carbon structure of these fatty acids is “saturated” with hydrogen atoms.8
The official saturated fat definition is any fatty acid with no double bonds present between the carbon molecules. It is simply a type of fatty acid found in a variety of foods, including meat and dairy products.
You may have heard over the years that saturated fat is on the naughty list for raising LDL. But new studies show that eating more saturated fat is also associated with an increase in HDL, resulting in a decrease in total cholesterol.9
Saturated fats to eat are full-fat-dairy products like butter, cheese, and cream; lard, and solid oils like coconut.9
Trans fats
Short for “trans fatty acids,” trans fat appears in foods that contain partially hydrogenated vegetable oils. These are the worst fats for you. You might find trans fat in:
- fried foods (French fries, doughnuts, deep-fried fast foods)
- margarine (stick and tub)
- vegetable shortening
- baked goods (cookies, cakes, pastries)
- processed snack foods (crackers, microwave popcorn)10
What is hydrogenated oil?
Hydrogenated oil is a type of fat that food manufacturers use to keep foods fresher for longer. Hydrogenation is a process where manufacturers add hydrogen to a liquid fat, such as vegetable oil, to turn it into a solid fat at room temperature.
Foods that contain higher levels of hydrogenated oils include:11
- canned frostings
- baked goods
- margarine sticks
- coffee creamers
- snack foods
Starting in the 1980s, researchers began looking at the impact of trans fats on health. They found that they:12
- Raise LDL (“bad”) cholesterol
- Lower HDL, the “good” cholesterol
- Interfere with the function of the endothelial cells that line blood vessels.
- Lead to inflammation
- Increase the risk of heart attack
What is Cholesterol?
Cholesterol is a waxy substance. It’s not inherently “bad.” Your body needs it to build cells and make vitamins and other hormones. But too much cholesterol can pose a problem.
Cholesterol comes from two sources. Your liver makes all the cholesterol you need. The remainder of the cholesterol in your body comes from foods from animals. For example, meat, poultry, and dairy products all contain dietary cholesterol.13
The two types of cholesterol are:
- Low-density lipoprotein (LDL) cholesterol. LDL, or “bad,” cholesterol can build up in the walls of arteries, making them hard and narrow.
- High-density lipoprotein (HDL) cholesterol. HDL, or “good,” cholesterol picks up excess cholesterol and takes it back to the liver.
Too much of the bad kind, or not enough of the good kind, increases the risk of high cholesterol levels in the blood that might lead to atherosclerosis and heart problems.
The function of cholesterol?13
Cholesterol has many important functions in your body. These include:
- Helping your cell membranes form protective layers. These layers control what can enter or leave your cell.
- Helping your liver make bile, which you need to digest food.
- Supporting your body’s production of certain hormones (including sex hormones) and vitamin D.
Healthy fats: The power of omega-3s14
Omega-3 fatty acids are a type of polyunsaturated fat and are especially beneficial to your health. There are different types of omega-3s: EPA and DHA are found in fish and algae and have the most health benefits, while ALA comes from plants and is a less potent form of omega-3, although the body does convert ALA to EPA and DHA at low rates.
Research has shown that a diet rich in omega-3s may help to:
- Prevent and reduce symptoms of depression, ADHD, and bipolar disorder.
- Protect against memory loss and dementia.
- Reduce the risk of heart disease, stroke, and cancer.
- Ease arthritis, join pain, and inflammatory skin conditions.
- Support a healthy pregnancy.
- Battle fatigue, sharpen your memory, and balance your mood.
Omega-3 foods to Eat 15
- Fatty Fish: Include fish high in omega-3 fats at least twice per week. For example, salmon, herring, sardines, lake trout, and Atlantic or Pacific mackerel.
- Walnuts: Walnuts are a plant-based source of omega-3 fatty acids. Add walnuts to cereal, salads, or muffins. Try walnut oil in salad dressings and sautés.
- Flaxseed: Your body cannot break down whole flaxseeds to access the omega-3-containing oil, so to get the health benefits, select ground flaxseed. Add it to breakfast cereal, yogurt, baked goods including breads and muffins or mixed dishes and casseroles. Or drizzle flaxseed oil over quinoa or use it for salad dressing.
- Chia seeds: These small seeds are packed with nutrients. In addition to omega-3s, they contain protein, dietary fiber and vitamins and minerals. Toss them in in your cereal, salads, and even baked goods.
- Hemp seeds: These seeds are also packed with omega-3s and protein. They can be eaten raw, cooked, or toasted.
- Other nuts: In addition to heart-healthy fats, nuts are a good source of protein, dietary fiber and a variety of vitamins and minerals. Just keep portion control in mind and choose unsalted forms. One portion of nuts is equal to 1 ounce and provides approximately 160 to 180 calories. Enjoy a small handful of nuts instead of chips or other fried snacks.
- Avocado: Avocados not only contain monounsaturated fat, but they also are packed with dietary fiber, potassium, and vitamins (folate and vitamins B6, C and E). Try adding avocado to salad, pizza, soup, salsa, eggs, and sandwiches. Enjoy avocado spread on toast for breakfast.
What to know when cooking with oils?
Why good cooking oils matter15
When cooking oils are heated, particularly at high heat, they eventually reach their smoke point. This is the temperature at which the oil is no longer stable and begins to break down.
When oil breaks down, it begins to oxidize and release free radicals. These compounds can have negative health consequences, potentially causing cellular damage that may lead to disease development.
Furthermore, oils that reach their smoke point release a substance called acrolein, which can create an unpleasant burnt flavor. Airborne acrolein may be dangerous to your lungs.
Some healthier cooking oils that can withstand higher temperatures include:
olive oil, avocado oil, sesame oil, and safflower oil.
They also contain various unsaturated fatty acids, antioxidants, and other compounds that may offer health benefits.
On the other hand, some oils are better to use for cold preparations or as dietary supplements, but not recommended for high heat cooking. Some examples include:
fish oil, flax oil, palm oil, and walnut oil.
Check out Part 1 of our nutrition series: Protein in a Nutshell
Check out Part 2 of our nutrition series: What you need to know about carbohydrates
References
- Nutrition and health: The fundamentals/IHN course notes ↩︎
- https://medlineplus.gov/ency/patientinstructions/000104.htm ↩︎
- https://www.healtheuniversity.ca/EN/CardiacCollege/Eating/Fats/ ↩︎
- https://medlineplus.gov/ency/patientinstructions/000104.htm ↩︎
- https://openoregon.pressbooks.pub/nutritionscience/chapter/5a-function-of-fats/ ↩︎
- https://www.hsph.harvard.edu/nutritionsource/what-should-you-eat/fats-and-cholesterol/types-of-fat/#:~:text=Unsaturated%20fats%2C%20which%20are%20liquid,number%20of%20other%20beneficial%20roles ↩︎
- https://www.health.harvard.edu/staying-healthy/know-the-facts-about-fats ↩︎
- https://www.medicalnewstoday.com/articles/141442#saturated-fats ↩︎
- https://www.healthline.com/health/food-nutrition/healthy-fats-guidelines#healthy-fats\ ↩︎
- https://www.healthline.com/health/heart-disease/good-fats-vs-bad-fats#trans-fat ↩︎
- https://www.medicalnewstoday.com/articles/hydrogentated-oil ↩︎
- https://www.medicinenet.com/is_hydrogenated_oil_unhealthy_foods_contain_it/article.htm ↩︎
- https://www.heart.org/en/health-topics/cholesterol/about-cholesterol ↩︎
- https://www.helpguide.org/articles/healthy-eating/choosing-healthy-fats.htm ↩︎
- https://www.eatright.org/food/food-groups/fats/choose-healthy-fats ↩︎
