Today there is a lot of conflicting and confusing information available about dietary fat/oil and the effects on health and weight loss. This article is intended to explore the available scientific data and list out the pros and cons for commonly used oils. Depending on the smoke point and composition, the kind of cooking that is healthy with particular oil also needs to be explored. This is a nuanced topic and there will not be many simple answers. However, a lot of propaganda with baseless and wrong data can be addressed.
Basics of “Fat” or Lipids
Lipids are essential compounds that make up a lot of important tissues in our body such as brain, hormones, cell membranes etc. Our body needs a minimum amount of dietary fat for proper functioning. Cutting down fat below these levels will cause a plethora of health problems. However, this minimum requirement is somewhere around 40g per day. It is easily satisfied by a regular diet including some oil for cooking, and foods containing fat such as nuts, dairy(cheese, cream, milk), whole eggs and meat. If you are following a “low-fat” diet for some reason, it is good to analyze and ensure that you meet the minimum requirement. Entering the intake into apps like fittr or Myfitnesspal will help you check that your intake of fat is above the minimum range.
Categories (Chemical composition) and health effects
By chemical composition, fats can be split into:
- Saturated fat
- Unsaturated fat
This is the category of lipids with NO DOUBLE BONDS between Carbon atoms. The absence of double bonds make this category of fat very stable at high heat. In the natural form, oils/fats high in saturated fat also tend to have low omega 6 fat content which helps us maintain the balance(recommended by various studies) of unsaturated fats as well. These characteristics make saturated fats a great choice for all cooking methods.
This is the category of compounds with 1+ DOUBLE BONDS between Carbon atoms. At high heat, these double bonds tend to break and connect to other molecules. The orientation of the compound can change in this situation and it can get oxidized or turned into “trans-fat” which is very harmful for our health. However, some of these compounds are really good for our health in their natural form. Use these oils for low-heat cooking and be careful not to let them smoke. Avoid refined varieties which go through the process of hydrogenation since they tend to have harmful trans-fats. Cold pressed oils are safer.
The unsaturated fats are categorized on the basis of the number of Carbon-Carbon double bonds.
- Mono-unsaturated fat: 1 C-C double bond
- Poly-unsaturated fat: More than 1 C-C double bond
There are special kinds of unsaturated fats that are believed to have major effect on health.
- Omega3 fat
- Omega6 fat
- Trans fat
Omega3 and Omega 6
Omega 3 and omega 6 fats are named based on the position of the double bond with respect to a particular end of the compound. Omega 3 and omega 6 are both essential fats that our body cannot manufacture. However, omega 6 is widely available in many fat sources while omega 3 is only available is certain kinds of fish and flax/chia seeds in appreciable amounts. The ratio of omega3 and omega 6 fats is observed to be important for health. Chronic inflammation is correlated with an imbalance in the ratio(high amount of omega 6 and low omega 3). Hence,
Trans fat is formed by effect of industrial processing or heat on oils. It refers to a particular alignment of the fat molecule which is found to be harmful for our body. Refined oils are often found to contain trans fats and must be avoided. Also, avoid cooking with unsaturated fats at high heat to prevent formation and consumption of trans-fats.
- Saturated fat is not unhealthy contrary to popular belief. Infact, because it has little to no omega6 content, it promotes good omega3:omega6 ratio in a diet.
- Saturated fat is heat-stable at high temperatures and therefore the only kind of oil suitable for deep frying.
- Unsaturated fat containing high omega3 should be included in the diet to prevent inflammatory diseases. Some of the sources include fish such as anchovies and salmon as well as flax seeds and chia seeds.
- Examples of healthy saturated fats: Ghee, Butter, Coconut oil, animal sources such as fatty meat, eggs, dairy
- Example of healthy unsaturated fats: Olive oil, flax seeds, chia seeds, nuts like almond, walnut, animal sources such as fish, grass fed meat.
- Avoid refined vegetable oils like soybean, rice bran, canola etc which undergo huge amount of processing.
- Avoid frying foods in unsaturated fat. Use saturated fats like coconut oil/ghee for high heat cooking.