Fats are one of the three macronutrients that your body needs to function properly, along with protein and carbohydrates. But not all fats are created equal. Some fats can benefit your health, while others can harm it. Knowing the difference between healthy and unhealthy fats can help you make better dietary choices and protect your heart, brain, and overall well-being.
What are fats and why do you need them?
Fats are organic molecules that consist of carbon, hydrogen, and oxygen atoms. They are classified into different types based on their chemical structure and the number of double bonds between the carbon atoms. The main types of fats are saturated, unsaturated, and trans fats.
Fats have several important roles in your body, such as:
- Providing energy: Fats are the most concentrated source of calories, providing 9 calories per gram, compared to 4 calories per gram for protein and carbohydrates. Fats can also be stored in your body as a reserve of energy for later use.
- Supporting cell growth: Fats are essential components of the membranes that surround every cell in your body. They also help form the protective layer of myelin that covers your nerve cells and enables them to communicate.
- Absorbing nutrients: Fats help your body absorb fat-soluble vitamins, such as vitamins A, D, E, and K, which are vital for your vision, bone health, immune system, and blood clotting.
- Producing hormones: Fats are involved in the synthesis of hormones, such as estrogen, testosterone, and cortisol, which regulate your metabolism, reproduction, stress response, and other bodily functions.
- Enhancing flavor and texture: Fats add richness, creaminess, and crispiness to your food, making it more palatable and satisfying.
What are the unhealthy fats and how do they affect your health?
Unhealthy fats are those that can raise your levels of low-density lipoprotein (LDL) cholesterol, also known as "bad" cholesterol, in your blood. LDL cholesterol can build up in your arteries and form plaques, which can narrow or block the blood flow and increase your risk of heart disease, stroke, and other cardiovascular problems.
Saturated fats
Saturated fats are fats that have no double bonds between the carbon atoms, meaning they are fully saturated with hydrogen atoms. They are usually solid at room temperature, such as butter, lard, and coconut oil. Saturated fats are mainly found in animal products, such as meat, poultry, dairy, and eggs, but also in some plant sources, such as palm oil and cocoa butter.
Saturated fats can increase your LDL cholesterol levels, especially if you consume them in excess or replace them with refined carbohydrates, such as white bread, pasta, and sugar. However, not all saturated fats have the same effect on your cholesterol. For example, stearic acid, a type of saturated fat found in chocolate, has a neutral effect on your cholesterol, while lauric acid, a type of saturated fat found in coconut oil, can raise both your LDL and high-density lipoprotein (HDL) cholesterol, also known as "good" cholesterol¹.
The current dietary guidelines recommend limiting your intake of saturated fats to less than 10% of your total calories per day². This means that if you eat 2,000 calories a day, you should consume no more than 22 grams of saturated fat. However, some experts suggest that the quality and quantity of carbohydrates and unsaturated fats in your diet may be more important than the amount of saturated fat³.
Trans fats
Trans fats are fats that have at least one double bond between the carbon atoms, but the hydrogen atoms are attached on opposite sides of the bond, creating a trans configuration. They are usually liquid at room temperature, such as vegetable oils, but become solid when hydrogen is added to them through a process called hydrogenation. This process makes the oils more stable, shelf-stable, and suitable for frying and baking. Trans fats are commonly found in processed foods, such as pastries, cookies, cakes, pies, crackers, chips, margarines, and fast food.
Trans fats can increase your LDL cholesterol levels and lower your HDL cholesterol levels, making them the worst type of fat for your health⁴. Trans fats can also cause inflammation, insulin resistance, and endothelial dysfunction, which are all risk factors for heart disease, diabetes, and stroke⁵.
The current dietary guidelines recommend avoiding trans fats as much as possible². This means that you should limit your intake of foods that contain partially hydrogenated oils, which are the main source of artificial trans fats. You should also check the nutrition labels and ingredient lists of packaged foods and choose those that have 0 grams of trans fat per serving. However, keep in mind that foods that have less than 0.5 grams of trans fat per serving can still claim to have 0 grams of trans fat, so you may still be consuming some trans fat if you eat multiple servings of these foods.
What are the healthy fats and how do they benefit your health?
Healthy fats are those that can lower your LDL cholesterol levels and increase your HDL cholesterol levels, improving your blood lipid profile and reducing your risk of heart disease and stroke. They can also provide other health benefits, such as:
Modulating inflammation: Healthy fats can help reduce inflammation, which is a common cause of chronic diseases, such as arthritis, diabetes, and cancer.
Supporting brain function: Healthy fats can help maintain the structure and function of your brain cells, which are largely made of fat. They can also enhance your cognitive performance, memory, mood, and mental health.
Promoting weight management: Healthy fats can help you feel full and satisfied, reducing your appetite and calorie intake. They can also increase your metabolic rate and fat burning, helping you lose or maintain your weight.
The two main types of healthy fats are monounsaturated fats and polyunsaturated fats.
Monounsaturated fats
Monounsaturated fats are fats that have one double bond between the carbon atoms, meaning they are missing two hydrogen atoms. They are usually liquid at room temperature, but may become solid when refrigerated, such as olive oil, peanut oil, and avocado oil. Monounsaturated fats are mainly found in plant sources, such as olives, nuts, seeds, and avocados, but also in some animal products, such as pork, beef, and chicken.
Monounsaturated fats can lower your LDL cholesterol levels and increase your HDL cholesterol levels, improving your blood lipid profile and protecting your heart. Monounsaturated fats can also help regulate your blood sugar levels, reducing your risk of type 2 diabetes.
The current dietary guidelines recommend replacing some of the saturated fats in your diet with monounsaturated fats². This means that you should choose foods that are high in monounsaturated fats, such as olive oil, nuts, seeds, and avocados, over foods that are high in saturated fats, such as butter, cheese, and fatty meats. However, you should still consume monounsaturated fats in moderation, as they are still high in calories and can contribute to weight gain if you eat too much of them.
Polyunsaturated fats
Polyunsaturated fats are fats that have more than one double bond between the carbon atoms, meaning they are missing more than two hydrogen atoms. They are usually liquid at room temperature and when refrigerated, such as sunflower oil, corn oil, and soybean oil. Polyunsaturated fats are mainly found in plant sources, such as vegetable oils, nuts, seeds, and some green leafy vegetables, but also in some animal sources, such as fish, seafood, and eggs.
Polyunsaturated fats can lower your LDL cholesterol levels and increase your HDL cholesterol levels, improving your blood lipid profile and protecting your heart. Polyunsaturated fats can also help lower your blood pressure, prevent blood clots, and reduce irregular heartbeats, which are all risk factors for heart disease and stroke.
Polyunsaturated fats are further divided into two subtypes: omega-3 and omega-6 fatty acids. These are essential fatty acids, meaning your body cannot produce them and you need to get them from your diet. Omega-3 and omega-6 fatty acids have different roles and effects on your health, and the balance between them is important.
Omega-3 fatty acids
Omega-3 fatty acids are polyunsaturated fats that have the first double bond at the third carbon atom from the end of the chain. They are mainly found in fish, seafood, algae, and some plant sources, such as flaxseeds, chia seeds, walnuts, and soybeans. The three main types of omega-3 fatty acids are:
- Alpha-linolenic acid (ALA): This is the most abundant and the only essential omega-3 fatty acid, meaning you need to get it from your diet. ALA can be converted into the other two types of omega-3 fatty acids in your body, but the conversion rate is very low and depends on several factors, such as your age, gender, health status, and intake of omega-6 fatty acids.
- Eicosapentaenoic acid (EPA): This is a long-chain omega-3 fatty acid that can be synthesized from ALA or obtained directly from your diet. EPA is involved in the production of eicosanoids, which are hormone-like substances that regulate inflammation, blood clotting, and immune response.
- Docosahexaenoic acid (DHA): This is a long-chain omega-3 fatty acid that can be synthesized from EPA or obtained directly from your diet. DHA is the most abundant omega-3 fatty acid in your brain and retina, where it plays a crucial role in maintaining their structure and function.
Omega-3 fatty acids can provide various health benefits, such as:
- Lowering inflammation: Omega-3 fatty acids can reduce the production of pro-inflammatory eicosanoids and cytokines, which are involved in chronic inflammatory diseases, such as rheumatoid arthritis, inflammatory bowel disease, and asthma.
- Improving brain health: Omega-3 fatty acids can support the growth and survival of brain cells, enhance their communication and plasticity, and protect them from oxidative stress and neurodegeneration. Omega-3 fatty acids can also improve cognitive performance, memory, mood, and mental health, and prevent or delay the onset of Alzheimer's disease and other forms of dementia.
- Protecting eye health: Omega-3 fatty acids can prevent or treat dry eye syndrome, which is a common condition that causes irritation, inflammation, and blurred vision. Omega-3 fatty acids can also reduce the risk of age-related macular degeneration, which is the leading cause of blindness in older adults.
- Supporting heart health: Omega-3 fatty acids can lower blood pressure, triglycerides, and LDL cholesterol levels, increase HDL cholesterol levels, prevent blood clots, and reduce irregular heartbeats, which are all risk factors for heart disease and stroke. Omega-3 fatty acids can also reduce the risk of sudden cardiac death, which is caused by a fatal arrhythmia.
The current dietary guidelines recommend consuming at least 250 mg of EPA and DHA per day, which is equivalent to about two servings of fatty fish per week. However, some experts suggest that higher intakes of omega-3 fatty acids may be beneficial for certain populations, such as pregnant and lactating women, older adults, and people with cardiovascular or neurological disorders.
If you do not eat fish or seafood regularly, you can also get omega-3 fatty acids from plant sources, such as flaxseeds, chia seeds, walnuts, and soybeans, which are rich in ALA. However, you may need to consume more ALA to get the same amount of EPA and DHA, as the conversion rate is very low and varies among individuals. You can also take omega-3 supplements, such as fish oil, krill oil, or algae oil, which can provide concentrated doses of EPA and DHA. However, you should consult your doctor before taking any supplements, as they may interact with some medications or cause side effects, such as bleeding, nausea, or diarrhea.
Omega-6 fatty acids
Omega-6 fatty acids are polyunsaturated fats that have the first double bond at the sixth carbon atom from the end of the chain. They are mainly found in vegetable oils, such as sunflower, corn, soybean, and safflower oils, and in foods that are made with these oils, such as margarines, salad dressings, mayonnaise, and baked goods. The most common type of omega-6 fatty acid is:
- Linoleic acid (LA): This is the only essential omega-6 fatty acid, meaning you need to get it from your diet. LA can be converted into other types of omega-6 fatty acids in your body, such as arachidonic acid (AA), which is involved in the production of eicosanoids.
Omega-6 fatty acids can have both beneficial and harmful effects on your health, depending on the type and amount of omega-6 fatty acids you consume and the balance between them and omega-3 fatty acids.
- Beneficial effects: Omega-6 fatty acids can lower your LDL cholesterol levels and increase your HDL cholesterol levels, improving your blood lipid profile and protecting your heart. Omega-6 fatty acids can also help regulate your blood sugar levels, reducing your risk of type 2 diabetes.
- Harmful effects: Omega-6 fatty acids can increase inflammation, especially if you consume too much of them or too little of omega-3 fatty acids. Omega-6 fatty acids can also increase the production of pro-inflammatory eicosanoids, which are involved in chronic inflammatory diseases, such as rheumatoid arthritis, inflammatory bowel disease, and asthma.
The current dietary guidelines do not specify a recommended intake of omega-6 fatty acids, but they suggest limiting your intake of foods that are high in omega-6 fatty acids, such as vegetable oils and processed foods, and choosing foods that are high in omega-3 fatty acids, such as fish, seafood, nuts, and seeds. However, some experts suggest that the optimal ratio of omega-6 to omega-3 fatty acids in your diet should be between 4:1 and 1:1, as this may provide the best balance of anti-inflammatory and pro-inflammatory effects.
How to choose and use healthy fats in your diet ?
To reap the benefits of healthy fats and avoid the harms of unhealthy fats, here are some tips on how to choose and use fats in your diet:
Choose foods that are naturally high in healthy fats, such as fish, seafood, nuts, seeds, olives, avocados, and eggs, and eat them regularly.
Choose oils that are high in monounsaturated and polyunsaturated fats, such as olive, canola, peanut, sunflower, corn, and soybean oils, and use them sparingly for cooking, dressing, and seasoning.
Avoid or limit foods that are high in saturated fats, such as butter, cheese, cream, ice cream, fatty meats, poultry skin, and coconut and palm oils, and replace them with foods that are high in unsaturated fats, such as olive oil, nuts, seeds, and avocados.
Avoid or limit foods that contain trans fats, such as pastries, cookies, cakes, pies, crackers, chips, margarines, and fast food, and check the nutrition labels and ingredient lists of packaged foods and choose those that have 0 grams of trans fat per serving.
Balance your intake of omega-6 and omega-3 fatty acids, by eating more foods that are high in omega-3 fatty acids, such as fish, seafood, flaxseeds, chia seeds, walnuts, and soybeans, and less foods that are high in omega-6 fatty acids, such as vegetable oils and processed foods.
Consider taking omega-3 supplements, such as fish oil, krill oil, or algae oil, if you do not eat enough fish or seafood, or if you have a medical condition that requires higher intakes of omega-3 fatty acids, but consult your doctor before taking any supplements.
Conclusion
Fats are an important part of your diet, but not all fats are the same. Some fats can benefit your health, while others can harm it. Knowing the difference between healthy and unhealthy fats can help you make better dietary choices and protect your heart, brain, and overall well-being.
Healthy fats are those that can lower your LDL cholesterol levels and increase your HDL cholesterol levels, improving your blood lipid profile and reducing your risk of heart disease and stroke.
They can also provide other health benefits, such as modulating inflammation, supporting brain function, promoting weight management, and enhancing flavor and texture.
The main types of healthy fats are monounsaturated fats and polyunsaturated fats, which include omega-3 and omega-6 fatty acids.
Unhealthy fats are those that can raise your LDL cholesterol levels and lower your HDL cholesterol levels, making them the worst type of fat for your health.
They can also cause inflammation, insulin resistance, and endothelial dysfunction, which are all risk factors for heart disease, diabetes, and stroke. The main types of unhealthy fats are saturated fats and trans fats.
To reap the benefits of healthy fats and avoid the harms of unhealthy fats, you should choose foods that are naturally high in healthy fats, such as fish, seafood, nuts, seeds, olives, avocados, and eggs, and eat them regularly.
You should also choose oils that are high in monounsaturated and polyunsaturated fats, such as olive, canola, peanut, sunflower, corn, and soybean oils, and use them sparingly for cooking, dressing, and seasoning.
You should avoid or limit foods that are high in saturated fats, such as butter, cheese, cream, ice cream, fatty meats, poultry skin, and coconut and palm oils, and replace them with foods that are high in unsaturated fats, such as olive oil, nuts, seeds, and avocados.
You should also avoid or limit foods that contain trans fats, such as pastries, cookies, cakes, pies, crackers, chips, margarines, and fast food, and check the nutrition labels and ingredient lists of packaged foods and choose those that have 0 grams of trans fat per serving.
You should also balance your intake of omega-6 and omega-3 fatty acids, by eating more foods that are high in omega-3 fatty acids, such as fish, seafood, flaxseeds, chia seeds, walnuts, and soybeans, and less foods that are high in omega-6 fatty acids, such as vegetable oils and processed foods.
You may also consider taking omega-3 supplements, such as fish oil, krill oil, or algae oil, if you do not eat enough fish or seafood, or if you have a medical condition that requires higher intakes of omega-3 fatty acids, but consult your doctor before taking any supplements.
By following these tips, you can enjoy the delicious and nutritious benefits of healthy fats and protect your health and well-being.