Do Fats Make Us Fat?

This is the second of the 3-part macronutrient series. We will be discussing all things fats, as it is so easy to get confused about them. We’ll be talking about the functions, the myths surrounding it, and why fat doesn’t make you fat.

What role does fat play in our body?

The truth is, eating the right kind of fat is absolutely essential for good health and good bodily function.

1. Vitamin absorption: Fats play a critical role in the absorption of fat-soluble vitamins A, D, E and K. These vitamins dissolve in fat and therefore require fat in the diet in order to be absorbed. (1)

2. Building blocks (maintaining cell membranes): Fats are the primary building blocks of our cell membranes. This is especially important for babies and children when their bodies are still in a critical growth phase. (2) (3) (8).

3. Maintain brain function: Your brain is made up of primarily two things: cholesterol and fats, the majority of which are saturated fats. A diet that lacks fats deprives the brain of its natural building blocks and its ability to communicate with the rest of the body. (4) (5)

3. Maintains healthy skin and hair: Healthy fats play a vital role in maintaining healthy skin. (5) (6) (7)

4. Anti-inflammatory: Omega-3 fatty acids are known to have anti-inflammatory benefits in the body, reducing pain and supporting the immune system. (9) (10)

5. Hormone Balance: All of our hormones are actually made of fats. Omega-3 supplementation could reduce serum concentrations of testosterone and regulate menstrual cycles. (11)

6. Source of Energy: A major benefit of fat in the diet is its ability to supply energy. (12)

What types of fats should we be including in our diet?

Fats are typically grouped into three major categories:

1. Saturated fats

2. Monounsaturated fats

3. Polyunsaturated fats

4. Trans fats

Saturated fats

Found in animal products (meat, full fat dairy products), coconut oil, palm oil, cheese and ghee.

Recent studies have concluded that for the average individual, saturated fat has no significant association with heart disease.(13) (14) With that being said, there may be a small benefit to replacing saturated fat with unsaturated fat. This does not mean that saturated fats are ‘bad’ - just that some unsaturated fats are particularly healthier. Below we will explain the benefits of unsaturated fats.

Monounsaturated fats

Monounsaturated fats are found primarily in olives, avocados, olive oil, some nuts, like macadamias.

They lower ‘bad’ cholesterol (LDL) and raise ‘good’ cholesterol (HDL) and lower blood pressure. Monounsaturated fats are linked to reduced risk of cancer and diabetes.

Polyunsaturated fats

Polyunsaturated fats play both a structural and regulatory role in the body. They help form cell membranes, regulate gene expression, and aid in cell function.

Polyunsaturated fatty acids are further classified into two major types:

  1. Omega-3 fatty acids

  2. Omega-6 fatty acids

Our body doesn’t have the enzymes to produce them, so we must get them from our diet. Omega 3 and omega 6’s are essential in the diet in the correct ratio. However, most western diets contain too much omega-6 and not enough omega-3. The reason for this is because that western diets include large amounts of sunflower and corn oils (largely found in processed foods), grain-fed meat and margarines. These foods are all high in omega 6 and low in omega 3.

Important omega-3 fats (DHA and EPA) are found in cold-water fatty fish, like wild salmon, mackerel, herring sardines, anchovies, and bass, as well as in shellfish, like oysters and mussels.

Also, plant based sources of omega 3’s include: walnut, flaxseeds and flaxseed oil.

Trans Fat

These fats must be avoided or at least limited.

They are found in:

  • Fried food (e.g. chips, doughnuts, deep-fried fast foods)

  • Margarine

  • Baked goods (e.g. cookies, cakes, pastries)

‘Trans fats’ are a form of unsaturated fat that act more like a saturated fat because of their chemical structure. They are uncommon in nature but became a common choice for food manufacturers for use in margarine, snack food, packaged baked goods and frying fast food from around the 1950’s because the food industry wanted to ‘improve’ flavour stability and the shelf life of food.

Trans fats raise LDL cholesterol (‘bad’ cholesterol) and can also suppress HDL levels (‘good’ cholesterol). They are also linked to an increased risk for inflammation in the body. This inflammation can cause harmful health effects that may include heart disease, diabetes, and stroke.

Fat gives food flavour, helps keep us full longer and keeps us satisfied. Removing fat from food requires food manufacturers to add ingredients to actually make it taste good, specifically refined sugar, flours, thickeners, and salts. Thus making us crave more and ultimately eat more. So be careful whenever you see ‘low-fat’ foods.

Low Fat = High Sugar

Opt for fat-containing Greek yogurt or kefir that doesn’t have a lot of added sugar which will provide you with the benefits of the fat without the sugar.

Practical and simple tips to increase your healthy fat intake:

  • Fats to avoid/limit: deep fried food, meat pies, sausages, pastry, cakes and biscuits, margarine, sunflower and corn oil – these foods are highly processed, inflammatory and lacking in nutrients.

  • Include omega-3s DHA and EPA from fatty fish, shellfish, or fish oil.

  • Load up the diet with naturally occurring fats like nuts (walnuts, macadamia nuts, almonds, cashews and hazelnuts), seeds (flax, pumpkin, sunflower, sesame and chia) olives, avocado, cold-pressed coconut oil and olive oil, grass-fed butter, eggs (yolks included) and fatty cold water fish like salmon.

  • Choosing a serving of fat-containing Greek yogurt or kefir that doesn’t have a lot of added sugar which will provide you with the benefits of the fat without the sugar.



1) Dawson-Hughes B, Harris SS et al. (2015). Dietary fat increases vitamin D-3 absorption. J Acad Nutr Diet. 115(2):225-30.

2) Sarah K.Abbott, Paul L.Else, Taleitha A.Atkins, A.J. Hulbertab. (2012). Fatty acid composition of membrane bilayers: Importance of diet polyunsaturated fat balance. Biochimica et Biophysica Acta (BBA) – Biomembranes. 1818 (5): 1309-1317.

3) Ferreri, C., Masi, A., Sansone, A., Giacometti, G., Larocca, A. V., Menounou, G., Chatgilialoglu, C. (2016). Fatty Acids in Membranes as Homeostatic, Metabolic and Nutritional Biomarkers: Recent Advancements in Analytics and Diagnostics. Diagnostics (Basel, Switzerland), 7(1), 1.

4) Chianese R, Coccurello R, Viggiano A, Scafuro M, Fiore M, Coppola G, Operto FF, Fasano S, Laye S, Pierantoni R, Meccariello R. (2018). Impact of Dietary Fats on Brain Functions. Curr Neuropharmacol. 16(7):1059-1085.

5) De Mel D, Suphioglu C. (2014). Fishy business: effect of omega-3 fatty acids on zinc transporters and free zinc availability in human neuronal cells. Nutrients. 15;6(8):3245-58.

6) Pilkington S.M., Rhodes L.E. (2010) Omega-3 Fatty Acids and Skin. In: Krutmann J., Humbert P. (eds) Nutrition for Healthy Skin. Springer, Berlin, Heidelberg.

7) Black, H. S., & Rhodes, L. E. (2016). Potential Benefits of Omega-3 Fatty Acids in Non-Melanoma Skin Cancer. Journal of clinical medicine, 5(2), 23.

8) Strickland AD. (2014). Prevention of cerebral palsy, autism spectrum disorder, and attention deficit-hyperactivity disorder. Med Hypotheses. 82(5):522-8.

9) Li H, Ruan XZ, Powis SH, Fernando R, Mon WY, Wheeler DC, Moorhead JF, Varghese Z. (2005). EPA and DHA reduce LPS-induced inflammation responses in HK-2 cells: evidence for a PPAR-gamma-dependent mechanism. Kidney Int. 67(3):867-74.

10) Calder PC. n-3 polyunsaturated fatty acids, inflammation, and inflammatory diseases. (2006). Am J Clin Nutr. 83(6 Suppl):1505S-1519S.

11) Nadjarzadeh, A., Dehghani Firouzabadi, R., Vaziri, N., Daneshbodi, H., Lotfi, M. H., & Mozaffari-Khosravi, H. (2013). The effect of omega-3 supplementation on androgen profile and menstrual status in women with polycystic ovary syndrome: A randomized clinical trial. Iranian journal of reproductive medicine, 11(8), 665–672.

12) Freemantle E, Vandal M, Tremblay-Mercier J, Tremblay S, Blachère JC, Bégin ME, Brenna JT, Windust A, Cunnane SC. (2006). Omega-3 fatty acids, energy substrates, and brain function during aging. Prostaglandins Leukot Essent Fatty Acids. 75(3):213-20.

13) Siri-Tarino PW1, Sun Q, Hu FB, Krauss RM. (2010). Meta-analysis of prospective cohort studies evaluating the association of saturated fat with cardiovascular disease. Am J Clin Nutr. 91(3):535-46.

14) Hooper L, Martin N, Abdelhamid A, Davey Smith G. (2015). Reduction in saturated fat intake for cardiovascular disease. Cochrane Database Syst Rev. 10;(6):CD011737.


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