Everything You Need to Know About Unsaturated Fats
Fat gets a lot of bad publicity, but it's one of the three nutrients (protein and carbohydrates are the other two) needed to provide the body with calories. In addition to supplying energy, fat is essential for maintaining several other bodily functions.
It keeps us from feeling hungry, carries vitamins, insulates the body, helps to regulate blood sugar, and aids in cell repair in joints, organs, skin, and hair. There is also evidence that fat is useful in maintaining mental clarity, memory, and hormone production.
The problem with fat is not the fat itself, but the amount and kind of fat in the average American diet. Too many people are eating the wrong kind of fat too often. Too much dietary fat is one the main reasons an estimated 60 percent of Americans are overweight or obese.
While all fat has nine calories per gram, the excessive intake of dietary fat can lead to inflammation and illness. It's often believed that eating fat makes people fat, but the truth is that taking in too many calories is what makes people fat. Fat has twice as many calories as carbs and protein, so eating fatty foods makes it easier to consume more calories while eating less food.
One type of fat, saturated, is also a major cause of elevated low-density lipoprotein (LDL) or "bad cholesterol" that can lead to heart disease.
Unsaturated Fats by the Numbers
The number of times per week, according to the American Diabetes Association (ADA), that we should eat non-fried fish.
The number calories per gram of fat.
The recommended intake of total fat to total calories.
The approximate percentage of dietary fat that should come from unsaturated sources.
How Unsaturated Fats Work
There are two types of healthy fats: monounsaturated and polyunsaturated. They are referred to as healthy or "good" fats primarily because they can lower LDL cholesterol.
However, even "good" fats have their downside. Too much fat, regardless of the kind, can mean too many calories, weight gain, and health problems. Vegetable shortening is unsaturated, but when used to fry foods, it’s unhealthy. It contains trans fats, which raises LDL cholesterol and decreases good (HDL) cholesterol. This artery-clogging fat is found in processed foods such as cookies, crackers, pies, pastries, margarine, and, in small quantities, in meat and dairy products.
The trans fats in meat and dairy products are different from the trans fat in vegetable shortening. These trans fats are naturally occurring and may be good for us. Vegetable shortening is made by taking a monounsaturated fat and attaching hydrogen to it to create a kink in the single chain. This kink is called trans and our bodies don't recognize it.
Monounsaturated fats remain in liquid form at room temperature, but solidify when refrigerated. Foods high in monounsaturated fat include:
- olive, canola, and peanut oils
- sesame seeds
- nuts (almonds, cashews, pecans, peanuts)
The ADA recommends eating more monounsaturated fats than saturated fats, but amounts aren't required to be on food labels.
Polyunsaturated fats are usually found in liquid form, regardless of the temperature at which they are stored. Foods high in polyunsaturated fats include:
- cold-water fatty fish
- pumpkin seeds
- sunflower seeds
- oils (corn, soybean, sunflower)
One type of polyunsaturated fat, omega-3 fatty acids, have been shown to reduce the risk of heart disease and lower blood pressure. It's also part of the process in blood clotting, digestion, muscle contraction, making arterial walls pliable, and guarding against inflammation.
Omega-3s are found primarily in cold-water fatty fish such as salmon, sardines, rainbow trout, mackerel, and herring, but also in walnuts, flaxseed, flax oil, avocado, cauliflower, and walnuts. Omega-3 is widely available in over-the-counter supplements.
A report in the Journal of the American College of Cardiology recommends that healthy people consume at least 500 mg per day of omega-3 or 800-1,000 mg per day for people with cardiovascular disease. The ADA recommends eating non-fried fish two or three times a week.
The American Heart Association (AHA) offers the following recommendations regarding omega-3 fatty acid intake:
|Patients without documented coronary heart disease (CHD)||Eat a variety of (preferably fatty) fish at least twice a week. Include oils and foods rich in alpha-linolenic acid (flaxseed, canola and *soybean oils)|
|Patients with documented (CHD)||Consume about 1 g of EPA+DHA (preferably from fatty fish). EPA+DHA capsule form could be considered in consultation with the physician.|
|Patients who need lower triglycerides||2-4 g of EPA+DHA per day provided as capsules under a physician's care.|
*Soybean oil is 60 percent omega-6 fatty acid.
Patients taking more than 3 g of omega-3 fatty acids from capsules should do so only under a physician's care. High intakes could cause excessive bleeding in some people.
How to Work Unsaturated Fats Into Your Diet
Below are some specific ways to include unsaturated fats in your diet and limit saturated fats. The list appears in publications of the AHA and other health-related organizations.
- Use olive oil instead of butter for cooking, marinating, and making salad dressings.
- Bake with canola oil, not vegetable oil.
- Use nuts in place of other toppings for salads and as a healthy snack.
- Add avocado slices to sandwiches rather than cheese or mayonnaise.
- Eat fish (like salmon and mackerel) instead of meat once or twice a week.
- Replace fatty foods with fruits, vegetables, legumes, and whole grains.
- Take skin off chicken and limit fatty cuts of meat (meats with a lot of marbling), such as Porterhouse, rib-eye, and ribs, to once a month.
- American Diabetes Association
- American Heart Association
- Centers for Disease Control and Prevention
- Institute of Medicine
- Journal of the American College of Cardiology
- Medline Plus
- University of California San Francisco