The human body needs moderate amounts of dietary fats to function properly. Fats are an essential nutrient. They play an important role in maintaining overall health including brain function and mental health. Fats supply energy and essential fatty acids. They play an indispensable part in the chain of events that help regulate blood pressure, heart rate, blood vessel constriction, blood clotting, and the nervous system. Fat is required for the body to properly utilize the fat soluble vitamins A, D, E and K. Fat also helps maintain healthy hair and skin.

Though fats have 9 calories to a gram (verses 4 per gram for protein and carbohydrates) they are not quite the boogieman they were once thought to be. We now understand that some types of fat are better for us than others and some can actually be considered "heart smart" or good for our health. That's not to say we should make fats a large part of our diet as some popular diet plans suggest, but we can make wise decisions based on the best current science. We can empower ourselves to choose the healthiest fuels for our bodies and even use fats to our advantage.

The USDA 2005 Dietary Guidelines suggest we get between 20% and 35% of our daily calories from fats and oils. This means that if a person were on a weight loss diet of 1800 calories per day, they could eat up to 60 grams of fats and oils per day. To figure: multiply 1800 by 0.30 to get 540^-calories. Divide that by 9 (the number of calories per gram of fat) to get 60 grams of total fat. 

Most fats and oils have between 100 to 120 calories per measured tablespoon so it doesn't take a lot over the course of a day to reach 30 percent. Remember, fats and oils are found in many foods, including vegetables, so adding fats and oils to recipes or salad dressings adds up pretty fast.

Types of Fat

There are four main types of fat: Saturated, Trans-Fat, Polyunsaturated, and Monounsaturated.

Saturated

This fat is solid at room temperature. It is said to increase the risk of coronary artery disease. Examples of saturated fats are: meat, lard, poultry, whole milk, butter, egg yolk, most cheeses, palm and palm kernel oil, coconut oils, cocoa butter

Trans-Fats

Trans-fats, also referred to as trans-fatty acids, are unsaturated fats that can raise the levels of artery clogging bad cholesterol (LDL) and lower the good cholesterol (HDL). A most unhealthy combination. Some nutrition authorities believe trans-fats to be much more damaging to our health than saturated fats. The National Academy of Sciences—Institute of Medicine, has said there is no safe amount of trans fat in the diet. Trans-fats, found in all hydrogenated and partially hydrogenated vegetable oils, are used in the majority of packaged baked and snack goods, and for cooking in most restaurants and fast-food outlets. Most common margarines, vegetable oil spreads, and shortenings are made with hydrogenated oils so consequently contain trans-fat. Hydrogenated and partially hydrogenated vegetable oils are used extensively in "Junk Food" such as chips, cookies, french fries, and pastry.

Trans fats are a type of man-made fat that has been added to food products for decades. Fats are acids made up of chains of carbon atoms attached to hydrogen atoms. Through a process called hydrogenation, hydrogen atoms are added on opposite sides of carbon atoms in the chemical chain. Hence the word "trans," meaning, across from. The process results in fats that are semi-solid and have a long shelf life.

At this time, no one knows what the minimum safe level is for trans-fats, some believe it to be zero. The Food and Drug Administration has recently made a ruling that all food labels will have to include levels of trans-fat by 2006.  [More on trans-fats]

Polyunsaturated

These oils are liquid at room temperature and when stored in the refrigerator. They combine easily with oxygen when exposed to air and soon become rancid. Examples of oils that are high in polyunsaturated fats are: vegetable oils such as safflower, corn, sunflower, soy and cottonseed oils, many nuts and seeds.

Common cooking oils should be bought in small quantities and refrigerated to keep them from oxidizing. 

Monounsaturated

These oils are liquid at room temperature but start to solidify when refrigerated. Unlike polyunsaturated fat, monounsaturated is more resistant to oxidation—a process that leads to cell and tissue damage in your body. Examples of oils high in monounsaturated fats are: olive, canola and peanut oils, avocados, and most nuts.

Smoke Points*

Oils should never be overheated. When oils are heated above their "smoke point" their chemical structure changes. They are already breaking down (oxidizing) and creating free radicals. Free radicals are atoms or molecules with an unpaired electron. Unpaired electrons result in unstable and highly reactive atoms and/or molecules that can start a chain reaction in our body as they attempt to steal and pair up with electrons from other molecules. This in turn changes the structure of these molecules and turns them into free radicals. These chain reactions can wreak havoc with our DNA and cells. They have been implicated in various cancers, disease, and aging processes. The fumes or smoke from overheated oil has also been found to contain carcinogenic hydrocarbons. Oils that have been overheated should never be used.

Some oils have higher smoke points than others. Olive oil should never be used for frying, but is fine for light sautéing. Avocado oil can safely be used at higher heats. Flaxseed oil should never be heated. Highly processed oils tend to take higher heats than expeller or cold pressed natural and extra virgin oils. Most of the common popular commercial cooking oils are processed with very high heat and chemicals like hexane which some people consider damaging or dangerous.

Storage

Oils, particularly unrefined and natural oils, should be stored in a cool dark place to slow any natural oxidation processes. They do not keep forever and will go rancid.

Summary

Saturated fats can raise both good and bad cholesterol levels. Trans-fats raise the bad and lower the good. Polyunsaturated and monounsaturated fats lower the bad and raise the good. Eating less saturated fat and more unsaturated improves cholesterol levels and helps prevent heart disease. According to the USDA 2005 guidelines you should:

• Consume less than 10 percent of calories from saturated fatty acids and less than 300 mg/day of cholesterol, and keep trans fatty acid consumption as low as possible.
• Keep total fat intake between 20 to 35 percent of calories, with most fats coming from sources of polyunsaturated and monounsaturated fatty acids, such as fish, nuts, and vegetable oils.
• When selecting and preparing meat, poultry, dry beans, and milk or milk products, make choices that are lean, low-fat, or fat-free.
• Limit intake of fats and oils high in saturated and/or trans fatty acids.

Cold or expeller pressed natural oils retain more of the beneficial nutrients and health promoting qualities and may be a wise consideration for those who are interested in whole natural foods.

This web site is for informational purposes only and is not meant to serve as medical advice or to replace consultation with a professional dietician, nutritionist, physician, or mental health professional. None of the information presented within this web site is meant to diagnose, prescribe, or to administer to any physical or emotional ailments or conditions.