Many consumers have come to believe that fat in their diet is inherently unhealthy; that reducing dietary fats will decrease the risk of heart disease, regardless of the source.  More recent studies question that assumption as they find more nuanced findings on dietary fats.

In my practice and closer to home, I see people responding to this more recent information in their willingness to consume some fats they’d avoided, yet awareness of which fats are “healthy” can be a source of confusion.

Attempting to offer a little guidance, I’ve prepared a basic list of types of fats, what they do in the body and which foods they are found in.

The Different Types of Dietary Fats

1. Unsaturated Fats 

Both mono and polyunsaturated fats are associated with lower risk of cardiovascular disease, improved metabolic function, insulin function, brain function, and satiety (feeling “full”).  If you’ve heard controversy over “seed oils” (which contain polyunsaturated  fats) being inflammatory, you may find this article helpful. Different types of unsaturated fats provide different benefits for the body, so it’s important to get all types in our diets. Omega-6 oils are found in many common foods, so you generally don’t need to go out of your way to eat them. This is why I give emphasis to the MUFA’s and Omega-3’s (DHA and EPA in particular).  

• Monounsaturated fatty acids (MUFA): Found in olive oil, avocados, nuts, and seeds (and the oils pressed from them). They help reduce LDL (“bad”) cholesterol , increase HDL (“good”) cholesterol and decrease triglycerides. They may support insulin sensitivity.
• Polyunsaturated fatty acids (PUFA): Include omega-3 and omega-6 fatty acids.
  • Omega-3s:

• • • Present in animal sources like fatty fish (salmon, sardines, mackerel, tuna), eggs, dark meat chicken, shellfish, algae and cod liver oil. These oils are anti-inflammatory and play a major role in neurological health, immune function, and heart health. They are classified as EPA (eicosapentaenoic acid) and DHA (docosahexaenoic acid) and are generally more difficult to get in adequate amounts through diet, unless consumed as fatty fish twice a week.
    • Alpha-linolenic acid (ALA-) Most prominent in walnuts, chia seeds, and flaxseeds. These oils are also anti-inflammatory, support brain health, and protect against heart disease. The body can convert ALA into DHA and EPA but at levels which may be too low to be significant.

• • Omega-6s: Found in vegetable oils (soy, corn, sunflower, canola). They are rich in linoleic acid which is correlated with improved cardiometabolic health, especially when taking the place of higher levels of saturated fats in the diet. They’re essential but also easy to get enough of.

2. Saturated Fats 

Saturated fats are found mostly in animal based foods like meat, butter, full-fat dairy, coconut oil, and certain tropical oils like coconut and palm (the exception to the animal based rule). Until fairly recently, they were considered universally harmful, but current research now shows the following:

• “A major 2010 meta-analysis pooled the available research and found “no significant evidence” of a connection between saturated fat intake and coronary heart disease, stroke or total cardiovascular disease. A large 2015 meta-analysis further showed no association between saturated fat intake and all-cause mortality, cardiovascular disease mortality, coronary heart disease, ischemic stroke, or type 2 diabetes.” –Dr. Sarah Ballantyne, PhD

• “However, not all studies show a neutral health impact from saturated fats. For example, a 2021 meta-analysis showed a non-linear relationship between all-cause mortality and saturated fat intake, plateauing above 11% of calories coming from saturated fats. This study highlighted an increased cancer mortality risk with consumption of saturated fats; for every 5% of total calories coming from saturated fats, cancer-related deaths increased by 4%.” –Dr. Sarah Ballantyne, PhD

• As you can see, guidance on saturated fat intake remains unclear.  Given the body of literature we have today, it seems that most people will do well with small to moderate amounts of saturated fats in their diet, and preferably from minimally processed sources  (meat, dairy, coconut). Some research does seem to indicate that excess intake of saturated fats, especially from highly processed foods, can raise LDL cholesterol and increase cardiovascular risk (attacks not mortality from attacks though). This is particularly harmful when combined with refined carbohydrates and a low fiber intake.

• Most of the population will not be negatively affected by small to moderate amounts of saturated fat in an otherwise varied diet, but there are people who are genetically more sensitive to dietary saturated fat. People who have a gene called ApoE4, are likely to see a spike in LDL with increased saturated fat intake. These people would do well to take greater care to limit their saturated fat intake than the average person.

• Overall,  emphasizing unsaturated fats in your diet is still recommended.

3. Trans Fats 

These oils are no longer as common because they are banned or heavily restricted.  They have been clearly shown to increase cardiovascular disease risk by raising LDL cholesterol, lowering HDL (“good”) cholesterol, and driving inflammation. Looking at food packaging, they are labeled as “hydrogenated” oils. Natural trans fats found in small amounts in dairy and meat (ruminant trans fats) don’t carry the same health risks.

Practical Tips for Choosing Fats

1. Prioritize whole-food sources. Nuts, seeds, avocados, olives, and fatty fish deliver healthy fats along with fiber, vitamins, and minerals which help reduce chronic disease risk. Other whole food sources like meats and full fat dairy have nutrients like stearic acid and vitamin K2, which have a positive impact on cardiovascular health.
2. Cook smart. Use olive oil for low- to medium-heat cooking and salads. Coconut oil and ghee handle higher heat better. Save flax and sesame oil for drizzling, not frying.
3. Balance omega-3 and omega-6. Aim for two servings of fatty fish per week or add algae-based omega-3s daily
4. Don’t fear fat. When eaten in the right form, fat enhances satiety, enjoyment of food, stabilizes blood sugar, and reduces cravings!

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