Healthy Fats vs. Unhealthy Fats

For years, fat was a three-letter word that we were urged to banish from our diets whenever possible. We switched to low-fat foods but the shift didn't make us healthier, probably because we cut back on healthy fats as well as harmful ones.

You may wonder isn't fat bad for you, but your body needs some fat from food. It's a major source of energy. It helps you absorb some vitamins and minerals. Fat is needed to build cell membranes, the vital exterior of each cell, and the sheaths surrounding nerves. It is essential for blood clotting, muscle movement, and inflammation. For long-term health, some fats are better than others. Good fats include monounsaturated and polyunsaturated fats. Bad ones include industrial-made trans fats. Saturated fats fall somewhere in the middle.

Trans Fats

The worst type of dietary fat is the kind known as trans fat. It is a byproduct of a process called hydrogenation that is used to turn healthy oils into solids and to prevent them from becoming rancid. Trans fats have no known health benefits and that there is no safe level of consumption. Therefore, they have been officially banned in the United States.

Eating foods rich in trans fats increases the amount of harmful LDL cholesterol in the bloodstream and reduces the amount of beneficial HDL cholesterol. Trans fats create inflammation, which is linked to heart disease, stroke, diabetes, and other chronic conditions. They contribute to insulin resistance, which increases the risk of developing type 2 diabetes. Even small amounts of trans fats can harm health: for every 2% of calories from trans fat consumed daily, the risk of heart disease rises by 23%.

Saturated Fats

Saturated fats are common in the Canadian diet. They are solid at room temperature — think cooled bacon grease, but what is saturated fat? Common sources of saturated fat include red meat, whole milk and other whole-milk dairy foods, cheese, coconut oil, and many commercially prepared baked goods and other foods.

Is saturated fat bad for you? A diet rich in saturated fats can drive up total cholesterol, and tip the balance toward more harmful LDL cholesterol, which prompts blockages to form in arteries in the heart and elsewhere in the body. For that reason, most nutrition experts recommend limiting saturated fat to under 10% of calories a day.

Monounsaturated and Polyunsaturated Fats

Good fats come mainly from vegetables, nuts, seeds, and fish. They differ from saturated fats by having fewer hydrogen atoms bonded to their carbon chains. Healthy fats are liquid at room temperature, not solid. There are two broad categories of beneficial fats: monounsaturated and polyunsaturated fats.

Monounsaturated fats. When you dip your bread in olive oil at an Italian restaurant, you're getting mostly monounsaturated fat. Monounsaturated fats have a single carbon-to-carbon double bond. The result is that it has two fewer hydrogen atoms than a saturated fat and a bend at the double bond. This structure keeps monounsaturated fats liquid at room temperature.

Good sources of monounsaturated fats are olive oil, peanut oil, canola oil, avocados, and most nuts, as well as high-oleic safflower and sunflower oils. Although there's no recommended daily intake of monounsaturated fats, the Institute of Medicine recommends using them as much as possible along with polyunsaturated fats to replace saturated and trans fats.

Polyunsaturated fats. When you pour liquid cooking oil into a pan, there's a good chance you're using polyunsaturated fat. Corn oil, sunflower oil, and safflower oil are common examples. Polyunsaturated fats are essential fats. That means they're required for normal body functions but your body can't make them. So you must get them from food. Polyunsaturated fats are used to build cell membranes and the covering of nerves. They are needed for blood clotting, muscle movement, and inflammation.

There are two main types of polyunsaturated fats: omega-3 fatty acids and omega-6 fatty acids. The numbers refer to the distance between the beginning of the carbon chain and the first double bond. Both types offer health benefits.

Good sources of omega-3 fatty acids include fatty fish such as salmon, mackerel, and sardines, flaxseeds, walnuts, canola oil, and unhydrogenated soybean oil.

Eating fat can be heart-healthy if you pick the right kind, and remember F-A-T is just a three letter word.

Matthew Clarke