The Truth About Fat and Cholesterol
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If you are even mildly interested in healthy eating and nutrition, then you have certainly come across this question: Is fat and cholesterol bad for you?
In my practice, I have heard numerous people say they are avoiding fat altogether. While some gurus and coaches say fat is the source of all dietary evil, entire diets (like keto) have been designed around eating high-fat meals — including drinking oil for some — every day. So who’s right and who’s wrong? Are fat and cholesterol to be avoided at all costs, or are they the healthiest foods ever?
“With so much information available about what to include and remove from your diet, knowing what to follow can be tricky,” says Sal Hanvey, a nutritionist with York Test.
The answer is somewhere in between.
Foods high in fat and cholesterol can be consumed as part of a healthy diet. But they should be eaten in limited quantities because they have plenty of calories per gram and some research suggests certain types (like saturated fat and trans fat) are linked to heart disease. Also, sources with added health benefits should be preferred. Think avocados, whole eggs, and plain Greek yogurt.
We spoke to experts, examined decades of research, and reviewed the current dietary guidelines of organizations like the American Heart Association, the U.S. Food and Drug Administration, and the UK's National Health Service (NHS). Here's what you need to know about fat and cholesterol.
What's Fat & How Does it Affect Your Body?
Fats are naturally occurring esters of glycerol and fatty acids, which are solid at room temperature. They’re the main components of animal and vegetable fat. The esters and fatty acids that are liquid at room temperature are called oils.
Fats provide energy for your body. A gram of fat provides 9 calories of energy, more than double the amount of energy you get from proteins or carbohydrates (4 calories per gram).
When your body has excess energy or calories, it stores whatever you don’t use as fat. All excess calories are stored as fat, even if you consume them as carbohydrates or protein.
The fat in your diet can be classified into three main types: saturated fat, trans fat, and unsaturated fat. Here’s what you need to know about each type.
These fats are typically solid at room temperature. They can be found in animal and plant-based foods, including:
Poultry, especially with the skin
Coconut and coconut oil
Palm fruit and palm oil
Palm kernel and palm kernel oil
These fats provide energy and flavor, but they should be consumed in small quantities. The American Heart Association recommends that saturated fats make up 6% or less of your daily calories for those who need to lower their cholesterol. That means if your daily calorie requirements are 2,500 calories, 150 of them can come from saturated fat. That's roughly 17 grams or about three-and-a-half teaspoons.
Saturated fats are linked with high levels of “bad” cholesterol. Studies show that reducing the saturated fat you eat and replacing it with other fats such as monounsaturated or polyunsaturated fat may lower your heart disease risk. Food sources of monounsaturated and polyunsaturated fats include nuts and nut butters, flaxseeds, fatty fish like salmon and sardines, olive and other oils.
Trans fat are unsaturated fatty acids that can occur naturally in food products from cows, goats, and sheep, but partially hydrogenated oil is also an industrially produced source.
Trans fat are found in foods like:
Non-dairy coffee creamer
Many commercially produced baked or fried foods
Meat and dairy products
Trans fats are the worst type of fat you can eat. They don’t provide any nutritional benefits and consuming them has been linked to a higher risk of premature death and coronary heart disease, possibly because of its effects on cholesterol; it lowers your “good” (high-density lipoprotein or HDL) cholesterol while increasing “bad” (low-density lipoprotein or LDL) cholesterol.
Unsaturated fats have at least one unsaturated carbon bond in their molecule. They’re usually liquid at room temperature, and there are two main types of them: monounsaturated and polyunsaturated.
Chemically speaking, monounsaturated fats are fat molecules with one unsaturated carbon bond. Most fats and oil sources contain a mix of different types of fats; rich sources of monounsaturated fat include:
Olives and olive oil
Peanuts, peanut butter, peanut oil
They can also be found in nuts and seeds like:
Monounsaturated fats are considered to be good for your health in several ways. Some of their benefits include:
Lowering “bad” cholesterol levels
Containing healthful compounds like polyphenols, which are anti-inflammatory, anti-cancer, and have other benefits
Helping grow and maintain your body's cells
Providing a rich source of vitamins and minerals
Lowering your risk of hypertension and heart disease.
However, these fats are still high in calories. Experts advise that you make them the bulk of the 30% dietary fat daily recommendation. Choose them instead of trans fat or unsaturated fats.
Polyunsaturated fats are — chemically speaking — fats that have more than one unsaturated carbon bond in their molecule. Polyunsaturated fats are healthy, and they may be liquid at room temperature, but solid when chilled. Your body can’t make some polyunsaturated fats, so you should include small amounts in your diet to remain healthy.
There are two types of polyunsaturated fats: omega-3 and omega-6.
Omega-3 fatty acids
Omega-3 fats are found mostly in fish oils. These are essential oils that your body can’t make, so the only way to get them is through your diet. Omega-3 fat is present in:
Fish such as mackerel, salmon, herring, tuna, sardines, catfish, cod, pollock, halibut, swordfish, kippers, trout
Nuts and seeds such as flaxseed, chia seeds, walnuts
Plant oils such as canola oil, soybean oil, flaxseed oil
Seafood such as oysters, crabs, mussels, shrimp, scallops, lobster
Fortified food such as some brands of infant formula, eggs, milk, soy products, and yogurt
Supplements such as krill, fish, cod liver, and algal oils.
Omega-3 fats have many health benefits; they:
Are good for your heart and blood vessels. They help:
Reduce the amount of triglycerides (a type of fat) in your blood
Lower your blood pressure
Lower your risk of having arrhythmias (irregular heart beats)
Slow the storing of plaque — a hard substance made of calcium, fat, and cholesterol that hardens and clogs your arteries
Improve you and your baby's health if you’re pregnant or breastfeeding
May lower your Alzheimer’s disease and dementia risk.
Omega-6 fatty acids
Omega-6 fats are usually found in plants. Sources include:
Soy and soybean oil
Sunflower seeds and oil
Healthy benefits include:
May help in blood sugar control
May reduce your diabetes risk
May help lower your blood pressure.
However, I don’t recommend omega-6 supplements for people because your body can easily get enough from your diet and too much of it can be converted to chemicals that are harmful to your health.
What Is Cholesterol & How Does it Affect Your Body?
Cholesterol is a waxy, fatty substance that’s made in your liver and body cells. You can also get it by eating animal food sources, such as:
Dairy foods like milk, cheese, butter, yogurt
Cholesterol is used for essential functions like:
Building and repairing body tissues
Producing hormones such as estrogen and testosterone
Making bile, which helps you digest food
Producing vitamin D.
Cholesterol needs help to move around your body through your bloodstream and it gets that help by pairing with lipoproteins.
The most important types are:
Low-density lipoprotein (LDL)
High-density lipoprotein (HDL)
LDL carries cholesterol to your blood vessels and may cause the buildup of plaque. Cholesterol associated with LDL is called bad cholesterol, and it's the type of cholesterol that's monitored closely. High levels of LDL are linked with an increased risk of heart attack, heart disease, and stroke.
HDL does the opposite. It carries cholesterol away from your blood vessels back to the liver, so it can be removed from your body. Cholesterol that's carried by HDL is often called good cholesterol.
You can lower your bad cholesterol by making healthy lifestyle choices, says Hanvey. Some ways to do this are:
Choosing a diet that's low in saturated and trans fats. Interestingly, most of the LDL cholesterol comes from these types of fats and not cholesterol in your diet.
Being physically active. About 150 minutes of vigorous activity each week is deemed adequate.
Aim for a healthy body weight. Losing extra weight can help lower your bad cholesterol and increase your good cholesterol.
How Should You Think About Fat and Cholesterol?
Foods rich in fat and cholesterol can be part of a healthy, balanced diet. But you need small quantities and the right types to reduce health risks.
To get the best out of fat-rich foods, you may:
Eat them in small quantities; they should account for 30% of your daily calories or less.
Get them from natural sources that also deliver other nutrients such as vitamins, minerals, and healthful compounds like polyphenols.
Choose more of the healthy types, such as monounsaturated and polyunsaturated fats, which have the most health benefits.
Cut back on saturated fats. Scientists don’t agree unanimously on whether saturated fats are associated with cardiovascular disease and death, so save the ribeye and cheeseburgers for occasional indulgences.
Avoid trans fats, which are linked to health conditions and have no health benefits.
Should You Worry About the Amount or Type of Fat You Eat?
Fats are present in so many foods that it's unlikely you’ll get too little of them. You may worry about getting too much of them in your diet if:
They make up more than 30% of your daily calories
You consume more than 10% of calories from unsaturated fats
Your diet is mainly processed foods, fried foods, or baked goods
You consume any food high in trans fat.
Should You Worry About Your Cholesterol Level?
Normal cholesterol levels in your blood should be 200 mg/dL or less. Your healthcare provider can help you check your cholesterol level regularly, depending on your age, risk factors, and family history. The general recommendations are:
For people age 19 or younger:
The first test should be between ages 9 to 11
Children should have the test again every 5 years
Some children may have this test starting at age 2 if there’s a family history of high blood cholesterol, heart attack, or stroke.
For people age 20 or older:
Younger adults should test every 5 years
Men ages 45–65 and women ages 55–65 should test every 1 to 2 years.
Fat and cholesterol have been vilified and worshiped in almost equal measure. But they can be part of a healthy diet if you choose the right amounts and types.
Monounsaturated and polyunsaturated fats from natural sources with additional health benefits and low health risks should be preferred. Saturated fat, which is linked to high levels of bad cholesterol in blood and health conditions, should be consumed in small quantities. Trans fat should be avoided because it has no benefits and considerable risks.