Good Fats vs Bad Fats: Which Ones Your Body Actually Needs

It can be overwhelming to stand in the supermarket and see so many oils, spreads, and labels that say “heart-healthy” or “low-fat.” Fat is one of the most confusing parts of healthy eating, especially when you are trying to figure out which types are good for you and which are not.

For a long time, people were told to avoid all fats. But new nutrition research shows that some fats are actually good for you. Some types of fat help your health, while others can raise your risk of heart disease and other problems if you eat too much of them.

You don’t need to cut out fat completely. The important thing is to know which fats help you and which ones you should eat less often.

Why Your Body Needs Fat

Fats do more than just add flavor to your food. They are essential for many basic body functions that happen every day without you even noticing.

Your body uses fat for long-lasting energy. While carbohydrates burn off quickly, fats help you feel full for longer. Fats also make your cell membranes stronger, support your brain, and help produce hormones that control things like your mood and metabolism.

Fats also help your body absorb vitamins like A, D, E, and K. If you don’t eat enough fat, your body can’t take in these vitamins properly, even if you eat foods that contain them.

One thing to remember is that fat has more calories per gram than protein or carbohydrates. Fat has 9 calories per gram, while protein and carbs each have 4. You don’t need to avoid fat, but it’s important to pay attention to how much you eat.

Understanding Different Types of Fat

All fats are made up of molecules called glycerol and fatty acids. The way these fatty acids are built affects how the fat acts in your body.

The number of double bonds in a fatty acid chain is what sets different fats apart. Monounsaturated fats have one double bond, polyunsaturated fats have more than one, and saturated fats have none, which is why they are solid at room temperature.

These small chemical differences change how fats taste and how they affect your cholesterol and inflammation in the body.

The Healthy Fats Your Body Needs

Some fats are good for your health. They protect your heart, help your brain, and keep inflammation in check.

Monounsaturated Fats

Monounsaturated fats, or MUFAs, are liquid at room temperature and get cloudy in the fridge. Olive oil is the most famous source, but you can also find MUFAs in avocados, nuts, and some oils.

You can get monounsaturated fats from olive oil, avocados, almonds, cashews, pecans, macadamias, peanut oil, sesame oil, and canola oil. Some animal foods, like pork and eggs, also have small amounts.

These fats are a big part of the Mediterranean diet, which research shows is linked to better heart health and fewer chronic diseases. Studies have found that swapping saturated fats for monounsaturated fats can improve your cholesterol and lower your risk of heart disease.

Monounsaturated fats raise your HDL cholesterol, which protects your heart, and lower your LDL cholesterol, which can block your arteries. They also help reduce inflammation, improve how your body uses insulin, and may help with a healthy weight. build up over time. You won’t feel dramatically different after one salad with olive oil dressing, but consistent choices can lead to measurable health improvements.

Polyunsaturated Fats

Polyunsaturated fats, or PUFAs, include omega-3 and omega-6 fatty acids. Your body can’t make these fats on its own, so you need to get them from food. That’s why they are called essential fatty acids.

Omega-3 sources include fatty fish like salmon, mackerel, and sardines, as well as plant foods like flaxseed, chia seeds, walnuts, and soybean oil. Omega-6 sources include sunflower oil, safflower oil, nuts, seeds, peanut butter, and grapeseed oil.

Both types play important roles. Omega-3s are particularly known for reducing inflammation and supporting brain health. They help lower LDL cholesterol, support cognitive function as you age, and may reduce the risk of depression and anxiety.

Omega-6 fats also have benefits, but most people already get plenty through vegetable oils and processed foods. The key is balance. Nutrition experts suggest that modern diets often contain too much omega-6 relative to omega-3, which can tip the balance towards more inflammation.

Adding more omega-3-rich foods while moderating omega-6 intake creates a better balance. This might mean eating fatty fish twice a week or sprinkling ground flaxseed on your morning porridge.

The Fats to Limit or Avoid

Some fats can harm your health if you eat them often or in large amounts.

1. Saturated Fats

Saturated fats are solid at room temperature. They’re the white fat you see on meat or the fat that solidifies when you refrigerate bacon grease. These fats mainly come from animal products, though coconut oil and palm oil are also high in saturated fat.

Common sources include butter, ghee, full-fat dairy products, cheese, fatty cuts of beef and lamb, chicken skin, lard, pastries, biscuits, cakes, and fried foods.

Eating too much saturated fat raises LDL cholesterol, which contributes to plaque build-up in your arteries. Over time, this increases your risk of heart disease and stroke. Research also links high saturated fat intake with increased blood pressure.

Experts suggest keeping saturated fat to about 5-6% of your total daily calories. For someone eating 2,000 calories per day, that’s roughly 11-13 grams of saturated fat, about the amount in 1 tablespoon of butter plus a small piece of cheese.

This doesn’t mean you can never eat these foods. It means being mindful about how often and how much. Choose lean cuts of meat more often. Use butter sparingly rather than lavishly. Pick lower-fat dairy options when it makes sense for your meals.

2. Trans Fats

Trans fats are the type that experts say you should avoid completely. They are found in very small amounts in some meat and dairy, but the main problem is artificial trans fats made by a process called hydrogenation.

This process changes liquid oils into solid fats to make processed foods last longer and have a better texture. But these fats are very bad for your health.

You can find trans fats in foods like margarine, shortening, packaged biscuits and cakes, microwave popcorn, fried fast food, and some ready-made pastries.

Even small amounts of trans fats can harm your health. They raise LDL cholesterol while simultaneously lowering HDL cholesterol, which is the worst possible combination. Trans fats also increase inflammation, raise your risk of type 2 diabetes, and may increase breast cancer risk, according to some research.

Many countries, including the UK, have worked to remove artificial trans fats from the food supply. But they can still hide in processed foods, so checking ingredient labels for “partially hydrogenated oils” remains important.

Taking Good Fats Every Day

You don’t have to count fat percentages at every meal. Making simple, practical swaps is what matters most.

Try cooking with olive oil or avocado oil instead of butter or lard. Snack on a handful of nuts instead of biscuits. Eat fatty fish like salmon or mackerel twice a week. Use avocado on your toast instead of butter, and pick natural peanut butter without extra oils.

When you eat saturated fats, enjoy them in smaller amounts. A little cheese goes a long way when paired with vegetables and whole grains. Choose lean cuts of meat and trim visible fat before cooking. Save fried foods and pastries for occasional treats rather than daily staples.

Read ingredient labels on packaged foods. Choose products that use olive oil, canola oil, or sunflower oil instead of palm oil or partially hydrogenated oils.

Building a Balanced Approach

Fat isn’t as bad as people once thought. Your body needs fat to work well. Often, whether you feel full of energy or tired depends on the types of fat you eat most often.

Healthy fats help your heart, support your brain, and keep inflammation under control. Unhealthy fats can put stress on your heart and raise your risk of disease over time.

You don’t have to be perfect—just consistent. When you make a habit of choosing better fats, the benefits add up. Your cholesterol gets better, your energy is steadier, your brain works better, and your risk of disease goes down.

Try making one small change this week. Switch your cooking oil, add nuts to your lunch, or have salmon for dinner. These simple steps can lead to better health over time.