Fat Facts


Women's Sports Medicine Center,
Hospital for Special Surgery

For a while now, fat has been frowned upon due to its role in promoting weight gain, obesity, and increased risk for heart attack, stroke, cancer, and diabetes. Fat helps food taste better, making these foods the ones we crave. Fat also performs many important functions in the body related to energy, vitamins and hormones. Like all other nutrients you eat, moderation is the key. Consuming too little or too much fat will ultimately lead to health problems. Itís critical to meet your daily needs in terms of amount and type of fat. Yet itís also important to avoid excess intake to prevent unnecessary weight gain, increased cholesterol levels, and greater risks for chronic disease.

Why do we need dietary fat?

Our bodies require a certain amount of fat every day to function properly. Fat is important because it:

  • gives you energy (9 calories per gram)

  • carries fat-soluble vitamins (vitamins A, D, E, and K) throughout your body

  • is important for normal functioning of hormones and enzymes and a critical part of cell membranes

  • provides essential fatty acids to your body

  • promotes satiety (making you feel full longer), since fats take longer to digest than other nutrients

What kinds of fat are there?

There are 3 main types of fat in foods: monounsaturated, polyunsaturated, and saturated. Not all fats are created equal, so itís important to understand the differences between them, including the types of foods in which they are found. Unsaturated fats may have a protective effect against heart disease, whereas saturated fat (the "bad" fat) has been known to increase risk of heart and other diseases. Our bodies are equipped to process some saturated fat; itís when we eat too much that health risks increase.

Type of Fat

Mono-unsaturated

Poly-unsaturated

Saturated

What it does

Decreases total cholesterol and lowers "bad" cholesterol (LDL), leaving HDL (good cholesterol) constant

Decreases total cholesterol and lowers "bad" cholesterol (LDL); may lower protective HDL.

Increases total cholesterol, which leads to increased risk of heart disease

Common foods

olive oil, canola oil, peanut oil, nuts, olives, avocados

 

 

fish (i.e. salmon, sardines, tuna, mackerel, herring), vegetable oils: corn, safflower, sunflower, sesame, soybean

butter, animal fats (whole milk, cheese, meat), baked goods, chocolate, fried foods, tropical oils (coconut, palm kernel)

What are trans-fats?

Trans-fatty acids, or trans-fats, are created through a process known as hydrogenation, which makes an unsaturated fat act like a saturated one. Small amounts of trans-fats also occur naturally in some foods, particularly animal products. Trans-fats are believed to increase total cholesterol in the body, which raises the risk for cardiovascular disease, cancer and other chronic diseases. Research on the long-term effects of trans-fats is mixed, and it is therefore recommended to avoid excess intake of these fats. Trans-fats are mostly found in processed foods, primarily in margarine, cookies, crackers and fried foods. They are often not listed on a food label, but may appear as "partially hydrogenated oils" or "vegetable shortening" in the ingredient list. Margarines or spreads with a liquid oil listed as the first ingredient are the healthiest choice. Tub margarine contains less trans-fatty acids than stick margarine!

What are essential fatty acids?

Essential fatty acids (EFA), commonly known as omega-3 and omega-6 fatty acids, must be consumed through food, since we are incapable of making them ourselves. Our bodies rely on EFAs to maintain cell structure and to produce nerve cells, hormones, and other compounds that regulate blood pressure, blood clotting, blood lipid levels, and immune response to injury and infection. We also use them for skin maintenance and normal hair growth. If EFAs are not consumed in our diet, the risk for developing a deficiency of EFAs is likely, leading to skin lesions, kidney and liver disorders, reproductive failure, neurological problems, and visual problems. Therefore, making sure you meet your daily requirements for fat is crucial. The two most important ones are linolenic and linoleic acid. Primary food sources for these fats are: seafood, nuts, seeds and vegetable oils.

Omega-3 fatty acids have been recognized for their potential health benefits, including possibly lowering blood cholesterol and helping in the prevention and treatment of heart disease, cancer, and hypertension. They may also help reduce the inflammation and swelling associated with rheumatoid arthritis and lupus. Omega-3 fatty acids found in fish may have additional protective effects against disease. These omega-3s are believed to help prevent blood clots (lowering chance of a heart attack) and may have positive effects on the brain, including benefits on mental health and possible lowered rates of depression. Omega-3 fatty acids are commonly found in shellfish and cold-water fatty fish, especially salmon, tuna, sardines, trout, mackerel and herring. Eating fish 2-3 times a week may be sufficient to reap benefits over time. Non-meat sources of omega-3 fatty acids include canola oil, flaxseed, walnuts and soybeans.

Some everyday tips for eating fat:

  • The average person should aim to get 20-30% (and no less then %15 Ė 20%) of their daily calories from fat, about 60-70 fat grams/day. Ideally this should be divided between monounsaturated (10-15%), polyunsaturated (10%) and saturated fat (< 7-10%).
  • Use fats containing unsaturated sources, such as nuts, seeds, vegetable oil and fish.
  • Limit your intake of foods containing trans-fats, ie. fast food, hydrogenated products, stick margarine, commercial baked products.
  • Include food sources of essential and Omega-3 fatty acids in your diet. (see above)
  • Use added fats and oils mindfully, ie salad dressings, fried foods, creamed sauces/gravies.
  • Choose lean versions of saturated fat sources such as lean meat and low fat dairy products.
  • The benefits of fish oils and other fat supplements are not clear. Getting these important nutrients from whole foods is recommended.

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