For decades, fats have been unfairly blamed for a host of health issues, particularly heart disease. However, emerging research challenges many of these misconceptions. In this article, we address the major myths surrounding this nutrient.
Fats – an introduction
Fats are a large range of molecules found in our body and the foods we consume. Some of the essential terms to understand with respect to fats:
- Saturated fats: fats with no double bonds. Solid at room temperature, these include dairy fats, coconut oil, and fats found in meats
- Mono-unsaturated fats: These fats have one double bond, and include the Omega-9 fats found in olive oil, avocados and nuts
- Poly-unsaturated fatsThese include the anti-inflammatory Omega-3 fats often found in seafood, walnuts and flax seeds; and Omega-6 fats found in most vegetable oils.
- Trans-fats: Artificially modified fats frequently used in bakery products and found in reused oils
- Triglycerides: The main form in which fats are stored in the body.
- Cholesterol: a waxy, fat-like molecule essential for cell membranes, hormonal production, and other crucial processes in the body.
- VLDL, LDL and HDL: These lipoproteins are transporters of fat in the bloodstream, with LDL often mislabeled as ‘bad cholesterol’ and HDL as ‘good cholesterol’
Myth: Fats are bad for you
Fats are most popularly known as the nutrient most responsible for cardiovascular disease.
Fact: Fats play several crucial roles in the body:
- Storehouse of reserve energy, leveraging on their high energy density
- Forming cell membranes and supporting nutrient absorption
- Major component of critical organs such as the human brain (~60% fat)
- Vehicle for the absorption of fat-soluble vitamins
- Involvement in critical physiological processes such as blood clotting, wound healing and inflammation
Myth: You should minimize fat intake
Fat intake guidelines around the world are remarkably consistent, recommending total dietary intake of 25-30%, with a further limit of 10% or lower for saturated fats.
Fact: Some of the healthiest diets on the planet – e.g., the Mediterranean Diet – have as much as 40-45% of their energy content as fat. Depending upon the kind of fats consumed, a healthy diet can contain significantly more fat than recommended in dietary guidelines.
Myth: Eating fat raises blood cholesterol
Popular science says that eating dietary fat, especially saturated fat, directly raises blood cholesterol levels. Therefore, fat intake should be minimized to maintain healthy cholesterol levels.
Fact: Most dietary fats do not directly translate to high blood cholesterol. The body tightly regulates cholesterol production—about 75% of blood cholesterol is produced by the liver converting blood glucose into cholesterol in a process called lipogenesis. More significant contributors to high blood cholesterol include refined carbohydrates, sugar, and insulin resistance.
Myth: High cholesterol causes cardiovascular disease
High LDL levels have been popularly identified as the primary driver of atherosclerosis (plaque formation in the arteries, leading to artery hardening and clots).
Fact: The primary trigger for atherosclerosis is chronic inflammation – triggered by high blood sugar, oxidative stress, infections, toxins and chronic. Inflammation damages the endothelium – the layer of cells lining blood vessels. In response to this damage, the body sends LDL cells for repair work. However, this repair process can backfire, as LDL molecules can oxidize inside the endothelium, eventually leading to plaque. Strategies for prevention of atherosclerosis need to focus on the root causes of inflammation as much as they do on managing circulating LDL – managing blood glucose levels through dietary and exercise interventions, avoidance of toxins from smoking and pollutants, managing stress, getting healthful sleep, and moderating alcohol intake.
Myth: Saturated Fats are bad and should be minimized
Saturated fats have been identified as the driver of high LDL and cholesterol.
Fact: Recent research challenges the idea that all saturated fats are harmful. Whole-food sources of saturated fats like dairy and coconut oil have neutral or even beneficial effects on health. These saturated fats increase HDL (the ‘good’ cholesterol), and increase the body’s production of large, buoyant LDL, which are not responsible for arterial plaque buildup.
Guidelines around saturated fat minimization lead to replacement of these calories by other macronutrients. Replacing saturated fats from ghee or butter with polyunsaturated fats from seed oils may actually be detrimental to health, as we shall see in the next myth. Replacing saturated fats with carbohydrates, especially refined carbohydrates, is certainly detrimental, leading to blood glucose spikes and high circulating LDL via lipogenesis.
Myth: Seed oils are the healthier fat choice
Oils from oilseeds such as sunflower, groundnut and soybean have long been promoted as the healthier fat variety in our diets.
Fact: Most seed oils are dominated by a class of PUFAs called Omega-6. Excessive intake of Omega-6 is a problem for two reasons. One, the body processes Omega-6 using the same enzymatic pathways as are used for Omega-3 processing, and excessive Omega-6 interferes with Omega-3 processing. Second, Omega-6 processing leads to pro-inflammatory molecules and increases the body’s propensity to accumulate fat accumulation in the body.
The overall verdict: An optimal Omega-6:Omega-3 ratio should be 3:1 or lower, but many modern diets exceed 15:1, contributing to chronic inflammation and metabolic issues. The best approach is to reduce Omega-6 intake while increasing Omega-9 (from olive oil, nuts, avocados) and stable saturated fats (from dairy, coconut oil).
Myth: Trans fats are unhealthy
No debate here – this is the one area around health guidance in unambiguous in recommending elimination of this nutrient from the diet. Trans fats enter our diets primarily in the form of hydrogenated vegetable oils (extensively used in baking) and through reuse of oils previously used in frying. In both of these forms, trans fats have been proven to increase LDL, decrease LDL and promote inflammation.
Conclusion
Fats are not the enemy - in fact, they are vital for good health. The key is to focus on quality of fat intake rather than arbitrary fat intake limits. Our final view:
- Depending on individual health goals, fats can be the largest source of calories in the diet.
- Prioritize: Omega-3s (fatty fish, flaxseeds), Omega-9s (olive oil, nuts), and natural saturated fats (dairy, coconut oil).
- Limit: Omega-6 PUFAs from seed oils.
- Eliminate: Trans fats from processed foods.