Why Fat and Cholesterol Are Both Important to Your Body

Fat and cholesterol are both essential to your body, but they're not the same thing — and there are good and bad kinds of both. Here's the difference between fat and cholesterol and what you should know about them.

​Read more:​ Your Ultimate Guide to Fats and Why Your Diet Needs Them

"Fat serves two purposes: It allows our body to function and helps us achieve satisfaction with food," says Robyn Goldberg, RDN, a nutrition therapist at Ask About Food in Beverly Hills, California. "Having fat in our diet helps to stabilize blood sugar levels [and] helps manage inflammation in the body, in addition to protecting organs and transporting fat-soluble vitamins."

Because fat plays a number of important roles in the body, the truth is a little more complicated than "fat is bad for you" or "fat is good for you." It's important to keep healthy fats in your diet, while limiting fats that are linked with health issues.

"Dietary fat is the broad term that covers many different types of fats (or lipids) that are consumed in the diet," says Sara Patton, RD, a member of the clinical nutrition team at Deborah Heart and Lung Center in Browns Mills, New Jersey. "The term 'fat' includes triglycerides, saturated fats (fats that are solids at room temperature, such as butter and coconut oil), unsaturated fats (fat that is liquid at room temperature, such as olive oil and canola oil) and sterols, a type of lipid (or fat) found in foods."

According to the Mayo Clinic, triglycerides are a type of fat found in the blood. When you eat, your body transforms extra calories into triglycerides. The triglycerides are then stored in fat cells until your body needs more energy, like between meals. A high triglyceride level is linked to an increased risk for heart disease and stroke.

"Dietary cholesterol is the most commonly occurring sterol in the diet," Patton says. "Cholesterol is found in the fatty part of animal products, such as butter, egg yolks, meats, whole milk and poultry. Cholesterol is important to our body as it helps create bile salt, which in turn helps emulsify lipids in our stomach prior to digestion."

The U.S. National Library of Medicine explains that your liver naturally makes cholesterol, and you can also get it from dietary sources. There are two main types of cholesterol: low-density lipoprotein (LDL), which is considered "bad" cholesterol, and high-density lipoprotein (HDL), also known as "good" cholesterol. High levels of LDL, the bad type of cholesterol, are linked to heart disease.

"After decades of research, it is clear that fat and cholesterol relate to heart disease in a complex way that we have yet to fully understand," says Carrie Lam, MD, co-founder and medical director of Lam Clinic in Tustin, California. "What is known is that there are good and bad fats, as there is good and bad cholesterol. The good fat and cholesterol are key macronutrients needed every day for optimum anti-aging health."

Rather than recommend a specific limit on dietary cholesterol (as it had in the past), the American Heart Association (AHA) now recommends that people stick to a healthy diet that emphasizes fruits, vegetables, whole grains, low-fat or fat-free dairy, lean protein, nuts, seeds and liquid vegetable oils. By doing so, you'll naturally reduce your intake of saturated fat that can boost your bad LDL cholesterol, according to the AHA's January 2020 science advisory in ​Circulation​.

According to the federal government's 2015–2020 Dietary Guidelines for Americans, foods that are high in saturated fats include processed meats, margarine, whole milk, coconut oil and certain snack foods like cookies. The Dietary Guidelines state that you should limit saturated fat intake to no more than 10 percent of your daily calorie intake. For example, if you consume 1,700 calories a day, no more than 170 of them should come from saturated fats.

On the other hand, unsaturated fat foods — or foods high in healthy fats — include salmon, olive oil, avocados and most nuts. Replacing saturated fats in your diet with these healthy fats can help lower LDL in the blood and your heart disease risk, according to the federal Dietary Guidelines.

​Read more:​ 15 Healthy Fat-Rich Foods to Add to Your Diet