Reviewed by Brian St. Pierre, MS, RD

Are there “good” and “bad” fats?

And how much fat, exactly, should a health-conscious person strive to eat?

In this article, we’ll talk all about fats, including the effects of certain fats on your health, plus how fats work in your body.

What is fat?

Fat, an essential macronutrient, plays a crucial role in maintaining the proper functioning of your body.

Fat is a concentrated energy source which contains more calories per gram than either carbohydrates or protein. (Fat contains 9 Calories per gram, whereas carbs and proteins contain 4 Calories per gram.) This energy supports your daily activities.

Fat also plays a pivotal role in your body’s ability to absorb specific vitamins and minerals, ensuring you get the most out of the nutrients you consume.

Fatty acids

All fats are made up of fatty acids.

These tiny building blocks are classified into three main categories: saturated, polyunsaturated, and monounsaturated. We’ll discuss each in more detail below.

Unsaturated fats

These fats, sometimes referred to as “healthy fats,” are your allies in the quest for a healthier lifestyle.

Monounsaturated fats in foods like avocados and olive oil are known for their heart health benefits.

Polyunsaturated fats, the dynamic duo of omega-3s and omega-6s found in nuts, seeds, and fish, help regulate inflammation and support brain health, and by extension, overall well-being.

Saturated fats

These fats, which are often solid at room temperature, are commonly found in animal products like butter and fatty cuts of meat, as well as plant foods like coconut and chocolate.

While they’re essential for some bodily functions, it’s wise to consume them moderately. High intake—over 10 percent of your daily calories—of saturated fats has been linked to higher cholesterol, and an increased risk of certain diseases.

What are trans fats?

Trans fats are created when liquid oils transform into solid fats through a manufacturing process called hydrogenation.

While trans fats enhance shelf life, they can wreak havoc on your health. Trans fats can raise bad cholesterol and increase heart disease risk. These are the only fats that we can confidently say are “bad” for health, and should be minimized or avoided.

Why is some fat considered healthy, and some unhealthy?

Not all fats are created equal.

Let’s go into some of the nuances of unsaturated and saturated fats.

The benefits of unsaturated fats

Unsaturated fats, on the other hand, actively contribute to your well-being.

Some of the ways these fats can help your body include:

• Monounsaturated and polyunsaturated fats may help lower bad cholesterol, and boost good cholesterol, creating a harmonious balance that supports cardiovascular health.
• Unsaturated fats work to quell inflammation in your body, reducing the risk of chronic diseases and fostering overall health.
• By providing steady, sustained energy and promoting satiety, whole foods rich in unsaturated fats can help maintain a healthy weight.
• Unsaturated fats assist in improving insulin sensitivity, reducing your risk of diabetes.
• Monounsaturated and polyunsaturated fats (especially omega-3s) are like brain food, promoting cognitive function and stable moods.

In other words, incorporating sources of unsaturated fats into your diet—from foods such as avocados, nuts, seeds, and olive oil—help support a healthier you.

What to consider when it comes to saturated fats

Unsaturated fats may, on the whole, offer more health benefits than saturated fats.

But that doesn’t mean saturated fats are inherently unhealthy.

Excess saturated fats are known to raise levels of LDL cholesterol, often referred to as the “bad” cholesterol. This can create a risk factor for heart disease, jeopardizing your cardiovascular health.

Moderating your intake of saturated fats—often found in red meat, full-fat dairy products, coconut, chocolate, and certain processed foods—can be a smart move for your long-term health. Most research suggests limiting saturated fats to about 10 percent of your daily calories.

The role of fat in your diet

What effect does fat have on your overall health? What does it do inside your body?

Let’s find out.

Role #1: Cell development

From infancy to maturity, your body’s cells depend on fatty acids for cellular development.

Omega-3 and omega-6 fatty acids are like the architects of your cell membranes. They determine the structure and function of these cellular gatekeepers, influencing what goes in and out.

Omega-3s, found in fatty fish like salmon and flaxseeds, work to keep inflammation in check. This helps prevent chronic diseases, plus supports overall health.

Omega-6s, abundant in sources like vegetable oils and nuts, orchestrate pro-inflammatory responses when needed. This doesn’t mean they’re bad; These controlled inflammations play crucial roles in healing and immune responses.

Role #2: Overall health

The right fats, particularly those in the unsaturated category, can shield you from some major health challenges.

Healthy fats help your heart. Emphasizing monounsaturated and polyunsaturated fats, moderating saturated fats, and avoiding trans fats promotes healthy cholesterol levels, and reduces the risk of blockages that lead to heart attacks.

You can also minimize your risk of stroke with your fat choices. Unsaturated fats contribute to good blood flow and prevent blood clots.

Role #3: Nervous system

Picture your nervous system as a complex communication network, and healthy fats as the high-speed data cables that keep it running seamlessly.

From the crown of your head to the tips of your fingers, fats ensure the smooth functioning of your brain and nervous system.

As the control center, your brain is a fat-rich organ, with nearly 60% of its structure composed of fats. (Omega-3 fatty acids are especially known for their brain-boosting abilities: They enhance cognitive function, support memory, and even contribute to mood regulation.)

Myelin, a protective sheath that covers nerve fibers, is predominantly composed of fats. This insulation ensures that signals are transmitted accurately and efficiently throughout your nervous system.

Role #4: Hormone health and function

Hormones serve as messengers in the body, and they influence a number of critical metabolic processes including (but not limited to) weight regulation, digestive health, skin quality, ovulation and reproduction, sleep, and energy levels.

Since hormones are made from a combination of fats and cholesterol, it’s crucial to include enough fat in your diet to support hormone production.

This is specifically important for sex hormones such as testosterone, estrogen, and progesterone. If dietary fat and cholesterol are too low, these hormones may stop being produced in optimal quantities, and you may experience symptoms of hormonal deficiencies.

Role #5: Source of micronutrients

Many minimally-processed fat sources also supply a slew of beneficial micronutrients and phytonutrients.

Avocados, for example, are a great source of fiber, magnesium, vitamin E, B vitamins, and folic acid. Nuts and seeds provide omega-3 fatty acids, fiber, and other beneficial compounds.

Role #6: Vitamin absorption

Fats don’t just provide crucial vitamins and minerals, they also facilitate the absorption of fat-soluble vitamins A, D, E, and K.

Vitamin A—vital for vision, immune function, and skin health—depends on fats to be metabolized and used in the body.

Vitamin D, often called the “sunshine vitamin,” is crucial for bone health, immunity, and more. But sunlight alone isn’t enough—fats are the facilitators that help your body absorb and use it effectively.

Vitamin E, a powerful antioxidant, thrives in the presence of fats. It reduces oxidative stress and inflammation, and protects the health of your cells.

Vitamin K, essential for blood clotting and bone health, benefits from fats, too. They assist in its absorption, ensuring it’s available when your body needs it.

How to incorporate more unsaturated fats into your diet

If you want to boost your intake of unsaturated fats to reap their benefits, a few strategic changes to your eating habits can help:

1. Embrace monounsaturated fats: Foods like olive oil, avocados, nuts, and seeds are your go-to sources of monounsaturated fats. Drizzle extra-virgin olive oil on salads, add slices of avocado to your sandwiches, and sprinkle nuts or seeds onto your morning yogurt for a delightful crunch.
2. Avoid trans fats: To get the best balance of dietary fats, minimize processed foods with trans fats. These artificially created fats can negatively impact your health, so read labels and opt for whole, minimally-processed options instead.
3. Seek out omega-3-rich foods: Omega-3 fatty acids boost brain function and fight excess inflammation. Salmon (and other fatty fish), flaxseeds, chia seeds, and walnuts are rich sources. Aim to include them in your meals a few times a week.
4. Moderate saturated fat sources: While some saturated fats are necessary and even beneficial, it’s wise to keep their intake in check. Limit red meat and butter consumption, opting for leaner cuts of meat and small to moderate amounts of butter.
5. Sprinkle in flavor and support satiety: A drizzle of olive oil on your vegetables, a sprinkle of nuts on your oatmeal, or a dollop of nut butter on your whole-grain toast can enhance both flavor and appetite regulation— without exceeding daily calorie requirements.

We can support you on your fitness journey

If you’re wondering where exactly to start, or how much fat you should be incorporating into your diet, we’re here to help.

Creating a nutrition and fitness plan can be daunting, but you don’t have to do it alone. Our Ultimate Macro Calculator can help you figure out the optimal proportions of all the macronutrients—fats, carbohydrates, and protein—that you need to meet your goals.

Precision Nutrition can help you build habits that improve your physical and mental health, bolster your immunity, help you manage stress, and get sustainable results.

ULTIMATE MACRO CALCULATOR