Fats—the Good, the Bad & the Questionable

FATS—THE GOOD, THE BAD & THE QUESTIONABLE

Just banish fats from our diets and our weight loss challenge would be met. But it ain’t necessarily so. We actually need fat from food. It’s a major source of energy, provides essential fatty acids, and delivers fat-soluble vitamins and minerals. Fat is also necessary to build cell membranes and the sheaths surrounding nerves.

There are several types of fat. Fats found in foods from plants and animals are known as dietary fat, a macronutrient. Your body can also make its own fat from taking in excess calories; If you eat more than you need, you’ll gain weight. The U.S. Department of Agriculture 2015-2020 Dietary Guidelines for Americans recommends that adults get 20% – 35% of their calories from fat. However as part of aging, seniors like us are likely to have more fat stores and less muscle mass. Thus, we need to consume fewer calories than we did when we were younger. And we should definitely work to limit our diets to the “good” fats.

Good Fats

Polyunsaturated fats, found mostly in corn, sunflower and safflower oils, are in the “good fat” category. They are essential fats, which means they’re required for normal body functions. Your body can’t make them, so you must get them from food. They help lower both blood cholesterol and triglyceride levels. Omega-3 fatty acids are one type of polyunsaturated fat that has been getting great press lately for their heart-health benefits. Good sources of omega-3 fatty acids include fatty fish such as salmon, mackerel and sardines plus flaxseeds and walnuts.

 

Monounsaturated fats are also “good” fats, which are thought to reduce the risk of heart disease. Olive oil contains mostly monounsaturated fat and is a big component of the healthy “Mediterranean diet.”   Other good sources are olives, avocados, hazelnuts, almonds, Brazil nuts, cashews, sesame seeds, pumpkin seeds plus canola and peanut oils.

Questionable Fats

Saturated fats are common in our American diet. They appear in red meat, whole milk and other whole-milk fairy foods, cheese, coconut oil and many commercially baked and processed foods. The studies are mixed on whether saturated fats are good or bad for us. A diet rich in saturated fats can drive up total cholesterol and for that reason most experts recommend limiting saturated fat to under 10% total calorie intake a day. Even better, would be to replace saturated fat with unsaturated (mono or poly) fats, which appear to reduce the risk of heart disease.

Bad Fats

There are “bad fats” which can be harmful. The worst is trans fat, which is mostly chemically manufactured and appears in many foods from commercial cookies and pastries to french fries at fast food restaurants. Trans fats increase the amount of harmful LDL cholesterol and reduce the amount of beneficial HDL cholesterol in the blood stream. They can also create inflammation and contribute to insulin resistance. On food label ingredient lists they are typically listed as “partially hydrogenated oil.”

Trans fats have no known health benefits and there is no safe level of consumption. Fortunately, the FDA is essentially banning it in processed food starting in 2018.

Fat Intake Recommendations

Here are diet suggestions from the Mayo Clinic (Read Article):

“Focus on replacing foods high in saturated fat with foods that include monounsaturated fats and polyunsaturated fats.

Still, don’t go overboard even on healthy fats. All fats, including the healthy ones, are high in calories. So consume monounsaturated and polyunsaturated fats instead of other types of fat, not in addition to them.

Here are some tips to help you make over the fat in your diet:

• To avoid trans fat, check food labels and look for the amount of trans fat listed. By law a serving of food containing less than 0.5 grams of trans fat can be labeled as 0 grams. Therefore, it’s important to also check ingredient lists for the term “partially hydrogenated.”
• Use oil instead of solid fats. For example, sauté with olive oil instead of butter, and use canola oil when baking.
• Prepare fish, such as salmon and mackerel, instead of meat at least twice a week to get healthy omega-3 fatty acids. Bake or broil seafood instead of frying.
• Choose lean meat and skinless poultry. Trim visible fat from meat and poultry, and remove skin from poultry.
• Snack smart. Many popular processed snack foods are high in fat, especially solid fats. Be sure to check food labels for saturated fat. Better yet, snack on whole fruits and vegetables.”

 

Addendum: Chemistry Anyone?

I used to have a hard time keeping the different fats straight. But learning a little about their chemistry, I finally got it. I’ve put the following together from a Harvard Medical School article (Read Article):

All fats have a similar chemical structure: a chain of carbon atoms bonded to hydrogen atoms (plus a couple of oxygen atoms). What makes one fat different from another is the length and shape of the carbon chain and the number of hydrogen atoms connected to the carbon atoms.

Saturated fats are solid at room temperature — think cooled bacon grease. The word “saturated” here refers to the number of hydrogen atoms surrounding each carbon atom. The chain of carbon atoms holds as many hydrogen atoms as possible — it’s saturated with hydrogens.

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.

A polyunsaturated fat has two or more double bonds in its carbon chain. 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.

The worst type of fat is 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). When vegetable oil is heated in the presence of hydrogen and a heavy-metal catalyst such as palladium, hydrogen atoms are added to the carbon chain. This turns oils into solids. It also makes healthy vegetable oils more like not-so-healthy saturated fats. On food label ingredient lists, this manufactured substance is typically listed as “partially hydrogenated oil.”