Research is continuing to evolve on dietary fat, but some facts are clear. Dietary fat — also known as fatty acids can be found in foods from both plants and animals. Certain fats have been linked to negative effects on heart health, but others have been found to offer significant health benefits.

Fat is as essential to your diet as protein and carbohydrates are in fueling your body with energy. Certain bodily functions also rely on the presence of fat. For example, some vitamins require fat in order to dissolve into your bloodstream and provide nutrients. However, the excess calories from eating too much fat of any type can lead to weight gain, according to Stanford Hospital and Clinics.

All foods and oils contain a mixture of fatty acids, but the predominant type of fat they contain is what makes them “good” or “bad.”

Two types of fats — saturated fat and trans fat have been identified as potentially harmful to your heart. Most of the foods that contain these types of fats are solid at room temperature, such as:

• butter
• margarine
• shortening
• beef or pork fat

Both saturated fat and trans fat should be avoided or eaten very sparingly.

This type of fat is primarily animal-based, and is found in high-fat meats and dairy products. Some typical sources of saturated fats include:

• fatty cuts of beef, pork, and lamb
• dark chicken meat and poultry skin
• high fat dairy foods (whole milk, butter, cheese, sour cream, ice cream)
• tropical oils (coconut oil, palm oil, cocoa butter)
• lard

Excess saturated fat has been shown to increase blood cholesterol levels and low-density lipoprotein (LDL) levels, which can increase your risk for heart disease and possibly type 2 diabetes, especially when combined with a diet high in refined carbohydrates.

Short for “trans fatty acids,” trans fat appears in foods that contain partially hydrogenated vegetable oils. These are the worst fats for you. You might find trans fat in:

• fried foods (French fries, doughnuts, deep-fried fast foods)
• margarine (stick and tub)
• vegetable shortening
• baked goods (cookies, cakes, pastries)
• processed snack foods (crackers, microwave popcorn)

Like saturated fat, trans fat can raise LDL cholesterol, also known as “bad” cholesterol. Trans fat can also suppress high-density lipoprotein (HDL) levels, or “good” cholesterol. Trans fats, therefore, can raise your heart disease risk threefold higher than saturated fat intake.

Monounsaturated fat and polyunsaturated fat are considered more “heart-healthy” fats, which you should include in your diet in moderation. Foods that primarily contain these healthier fats tend to be liquid when they’re at room temperature, such as vegetable oil.

This type of helpful fat is present in a variety of foods and oils. Research has consistently shown that eating foods that contain monounsaturated fat can improve your blood cholesterol level and decrease your risk of cardiovascular disease. These foods include:

• nuts (almonds, cashews, peanuts, pecans)
• vegetable oils (olive oil, canola oil, peanut oil)
• peanut butter and almond butter
• avocado

Plant-based foods and oils are the primary source of this fat. Like monounsaturated fat, polyunsaturated fat can decrease your risk of heart disease by lowering blood cholesterol levels.

A certain type of this fat, called omega-3 fatty acids, have been shown to be particularly beneficial for your heart. Omega-3s not only appear to decrease the risk of coronary artery disease, but also may help lower blood pressure levels and guard against irregular heartbeats. The following types of fatty fish contain omega-3 fatty acids:

• salmon
• herring
• sardines
• trout

You can also find omega-3s in flaxseed, walnuts, and canola oil, although these contain a less active form of the fat than fish do.

In addition to omega-3 fatty acids, you can find polyunsaturated fat in the following foods, which contain omega-6 fatty acids:

• tofu
• roasted soy beans and soy nut butter
• walnuts
• seeds (sunflower seeds, pumpkin seeds, sesame seeds)
• vegetable oils (corn oil, safflower oil, sesame oil, soybean oil, sunflower oil)
• soft margarine (liquid or tub)

Some margarines will contain trans fats if they are made with hydrogenated ingredients, so make sure to always choose non-hydrogenated versions. Labeling laws allow food companies to round down to zero and claim “no trans fats” or “zero grams of trans fats” despite still containing hydrogenated oils, so ignore the front-of-package marketing and always read the ingredient list.

Healthier fats are an important part of your diet, but it’s still crucial to moderate your consumption of them, because all fats are high in calories. Try replacing unhealthy fats with healthy fats when possible.

First, work on reducing foods in your diet that are high in saturated fat and trans fats. Then, make an effort to incorporate foods that contain monounsaturated and polyunsaturated fats. It’s a strategy that will help your heart and improve your quality of life.