Monday, April 26, 2010

Healthy fats? Truth or fact?

For over thirty years, fat in our diet has been considered the culprit in obesity, heart disease, and high cholesterol. Unfortunately, the resulting “low fat” foods and diets haven’t resulted in most people controlling their weight or becoming healthier. In fact, the opposite is true.
It’s the type of fat that matters in addition to how much you consume. Reducing your intake of some types of fats reduces the risk of several chronic diseases, but other types of fats are absolutely essential to our health and well-being.
Sifting through all the conflicting information on fats can leave you with even more questions. What do you need to know about polyunsaturated fat, omega 3 fatty acids and other terms in the language of fats? Learn to incorporate the good fats into your diet while reducing your consumption of the bad fats.

Myths and facts about fats and oils

Myth: Eating a low-fat diet is the best way to curb obesity.

Facts:
  • The obesity rates for Americans have doubled in the last 20 years, coinciding with the advent of the low-fat revolution.
  • In the 1960s, Americans ate 45% of their calories from fat – and only 13% of us were obese. Now, while most of us get only about 33% of our calories from fat, 34% of us qualify as obese!

Myth: Low–fat diets are essential to help you lose weight

Facts:
  • Ironically, cutting fat out of our diets seems to have the opposite effect: while Americans have been eating less fat, we’ve been getting fatter. In place of fats, many people turn to foods full of easily digested carbohydrates, or to fat-free products that replace healthful fats with sugar and high-calorie, refined carbohydrates.
  • You need to cut calories to lose weight - fats are more filling, and curbing hunger can stop you from indulging in additional calories.
  • The 2006 Women's Health Initiative Dietary Modification Trial showed that women on low-fat diets didn't lose any more weight than women who followed their usual diets. 

Healthy fats are essential to good health

The human body uses fatty acids to do everything from building cell membranes to performing key functions in the brain, eyes, and lungs. The functions of fats include:
  • Brain – Fats compose 60% of the brain and are essential to brain function, including learning abilities, memory retention and moods. Fats are especially important for pregnant women, since they are integral to fetal brain development.
  • Cells – Fatty acids help your cells stay moveable and flexible, as well as being responsible for building cell membranes.
  • Heart – 60% of our heart’s energy comes from burning fats. Specific fats are also used to help keep the heart beating in a regular rhythm.
  • Nerves – Fats compose the material that insulates and protects the nerves, isolating electrical impulses and speeding their transmission.
  • Lungs – Lung surfactant, which requires a high concentration of saturated fats, enables the lungs to work and keeps them from collapsing.
  • Eyes – Fats are essential to eye function.
  • Digestion – Fats in a meal slow down the digestion process so the body has more time to absorb nutrients. Fats help provide a constant level of energy and also keep the body satiated for longer periods of time. Fat-soluble vitamins (A, D, E, and K) can only be absorbed if fat is present.
  • Organs – Fats cushion and protect your internal organs.
  • Immune System –Some fats ease inflammation, helping your metabolism and immune system stay healthy and functioning.

"Faces" in the fat families

To understand good and bad fats, you need to know the names of the players and some information about them.

Monounsaturated fats

  • Are liquid at room temperature and turn cloudy when kept in refrigerator.
  • Primary sources are plant oils like canola oil, peanut oil, and olive oil. Other good sources are avocados; nuts such as almonds, hazelnuts, and pecans; and seeds such as pumpkin and sesame seeds.
  • People following traditional Mediterranean diets, which are very high in foods containing monounsaturated fats like olive oil, tend to have lower risk of cardiovascular disease.

Polyunsaturated fats

  • Are liquid at room temperatures as well as at cold temperatures
  • Primary sources are sunflower, corn, soybean, and flaxseed oils, and also foods such as walnuts, flax seeds, and fish.
  • This fat family includes the Omega-3 group of fatty acids, which are anti-inflammatory and your body can’t make. In addtion, Omega-3 fats are found in very few foods.

Saturated fat

  • Are usually solid at room temperature and have a high melting point
  • Primary sources are animal products including red meat and whole milk dairy products. Other sources are tropical vegetable oils such as coconut oil, palm oil and foods made with these oils. Poultry and fish contain saturated fat, but less than red meat.
  • Saturated fat raises low-density lipoprotein (LDL or "bad") cholesterol that increases your risk of coronary heart disease (CHD).
  • It is unnecessary to eat saturated fat sources since our bodies can produce all the saturated fat that we need when we consume enough of the good fats.

Trans Fats

  • Trans fats are created by heating liquid vegetable oils in the presence of hydrogen gas, a process called hydrogenation. Partially hydrogenating vegetable oils makes them more stable and less likely to spoil, which is very good for food manufacturers – and very bad for you.
  • Primary sources of trans fat are vegetable shortenings, some margarines, crackers, candies, cookies, snack foods, fried foods, baked goods, and other processed foods made with partially hydrogenated vegetable oils.
  • Trans fat raises low-density lipoprotein (LDL or "bad") cholesterol that increases your risk of coronary heart disease (CHD), as well as lowering HDL, or good cholesterol.