Dietary fats, what are they, the good and the bad

What is Fat?
In my blog post “What is nutrition?” I defined what fat is and it’s importance in our daily nutrition.

Fat is an essential nutrient because is gives our bodies energy, supports cell growth, and some vitamins are “fat soluble” which means our body will only absorb the vitamin if we combine it with fat (of course a healthy fat). Fats are broken down into three types, saturated, monounsaturated, and polyunsaturated. Avoid saturated fats as much as possible. Instead look for mono and poly unsaturated fats; they are heart healthy and help control cholesterol.

What are the types of fat?

There are four types of fats, saturated, trans fats, monounsaturated and polyunsaturated; and, each one has a different chemical structure and physical property. Fats can also have various effects on cholesterol (both the good HDL cholesterol and the bad LDL cholesterol. As we’ve already learned, above, while fats are essential for our bodies, some are good and some are bad. It’s very important to know the difference and avoid the bad fats.

Saturated Fats and what are they?

According to the American Heart Association (AHA), “from a chemical standpoint, saturated fats are simply fat molecules that have no double bonds between carbon molecules because they are saturated with hydrogen molecules. Saturated fats are typically solid at room temperature.” The AHA also states, “eating foods that contain saturated fats raises the level of cholesterol in your blood. High levels of LDL cholesterol in your blood increase your risk of heart disease and stroke.” Because saturated fats cause significant and serious health issues, it is recommended not to exceed more then 13 grams (or 5%) of your daily calories from saturated fats.

These are saturated fats and should be avoided or very limited

Examples of saturated fats are these foods

  • beef
  • lamb
  • pork
  • poultry with skin
  • beef fat
  • lard and creams
  • butter
  • cheeses
  • dairy products made from whole or reduced-fat (2 percent) milk

Trans fats and what are they?

There are two types of trans fats, naturally occurring and artificial. The AHA defines them as; “naturally-occurring trans fats are produced in the gut of some animals and foods made from these animals (eg: milk and meat products) may contain small quantities of these fats. Artificial trans fats (also called trans fatty acids) are created in an industrial process that adds hydrogen to liquid vegetable oils to make them more solid.” We primarily get trans fats from processed foods that contain “partially hydrogenated oils”.

WARNING: In November 2013, the U.S. Food and Drug Administration (FDA) made a determination that partially hydrogenated oils are no longer Generally Recognized as Safe (GRAS) in human food.

Food and Drug Administration

The FDA issued this warning because trans fats raise your bad LDL cholesterol and at the same time lower your good HDL cholesterol. Consuming trans fats adds significant increased risk of developing heart disease and stroke; along with higher risk of type 2 diabetes.

This is atherosclerosis – aka hardening of the arteries and it is caused by bad fats!

Examples of saturated fats are these foods

  • hydrogenated oils (look for this on ingredient list)
  • baked goods (doughnuts, cookies, crackers, muffins, pies, and cakes)
  • fried foods like those found at fast food restaurants
  • frozen pizza
  • refrigerated dough products (biscuits and cinnamon rolls)
  • vegetable shortening and stick margarine
  • nearly all fast foods
  • snack foods like microwave popcorn
  • coffee creamers
  • ready to use frostings

Monounsaturated and Polyunsaturated fats and what are they?

According to the Harvard School of Public Health “unsaturated fats, which are liquid at room temperature, are considered beneficial fats because they can improve blood cholesterol levels, ease inflammation, stabilize heart rhythms, and play a number of other beneficial roles. Unsaturated fats are predominantly found in foods from plants”. The AHA defines monounsaturated and polyunsaturated fats as fat molecules that have one unsaturated carbon bond in the molecule, this is also called a double bond. Oils that contain monounsaturated or polyunsaturated fats turn solid when chilled.

Monounsaturated and polyunsaturated fats help reduce bad cholesterol in your blood which can lower your risk of heart disease and stroke. They also provide nutrients to help develop and maintain your body’s cells. Oils rich in monounsaturated fats also add vitamin E to your diet, an antioxidant vitamin most Americans need more of, according to the AHA.

Monounsaturated and polyunsaturated fats – these are the “good” fats

Examples of monounsaturated fats are these foods

  • nuts (almonds, cashews, peanuts)
  • avocados
  • olive oil
  • canola oil
  • peanut oil
  • safflower oil
  • sesame oil

Omega-3 fats and what are they?

According to the Harvard School of Public Health (HSPH), omega-3 fats are an important type of polyunsaturated fat. The body can’t make these, so they must come from food. A good animal source of omega-3s is fish (2-3 times per week), good plant sources of omega-3s are flax seeds, walnuts, canola oil and soybean oil.

“Higher blood omega-3 fats are associated with lower risk of premature death among older adults, according to a study by the HSPH faculty.”

Harvard School of Public Health

Consumption of bad fats affects everyone at any age

As you’ve just learned there are good fats essential for our bodies, we simply couldn’t function without them; however, there are also bad fats and the effect they have on us accumulates over time. In the United States heart disease is the number one killer of both men and women, but, did you know there is a significant rise in heart disease in children too? According to the American Heart Association due to the increase in saturated fat children between the ages of 10 and 15 already have early signs of hardening of the arteries (atherosclerosis) and the rate is twice as high for teens between 15 and 20 years old. The AHA recommends that all children older than two years should begin following a heart-healthy nutrition plan low in saturated and trans fats including dairy products.

Heart disease is 100% preventable, eat a mostly plant-based diet, eliminate as much as possible saturated and trans fats and exercise at least three times per week. You’re heart and your loved ones will thank you!

2 thoughts on “Dietary fats, what are they, the good and the bad

  1. This is a very interesting article. I think this information should be getting out there more often! Is there a recommended daily amount for the good fats ie: Monounsaturated fats and polyunsaturated fats?


    1. According to the Mayo Clinic poly & mono fats should between 20-35% of daily calories. If you are on a 2,000 calorie per day plan, and fat is 9 calories per gram, that means 2000 times .20 or 400 calories and on the higher end 2000 times .35 or 700 calories. To get fat grams per day divided 400 by 9 which equals 44 grams per day at 20% and 700 divided by 9 which equals 78 grams per day on the high end.

      If you consume saturated fats those should be limited to no more than 10% of daily calories or 22 grams based on 2000 calorie per day plan.


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