Common Cooking Mistakes and How to Avoid Them

I hate to say it, but even if you are eating an allegedly super healthy meal you might be actually making something adverse to your health if you aren’t cooking it properly. For example, when cooking meat above 393°F, the amino acids contained within the meat form what are called “mutagenic compounds” that have been found to increase the risk of cancer (1).

When cooking meats and even vegetables using high heat, research has found increased formation of advanced glycation end-products (AGEs) in food. When we consume these compounds, we experience an increase in oxidative stress and inflammation. Research has even found a connection to AGEs and increased risk of cardiovascular disease and diabetes (2).

When it comes to using fats/oils for cooking, be aware that a lot of cooking oils out there are also not the healthiest. Check out my list below, where I look at some common oils and the reasons you may want to avoid/use them.

From my research, I found that you mainly want to understand the smoking point and fat composition. Smoking point is the temperature at which the particular oil begins, as the name implies – to smoke; meaning the temperature at which you are burning the oil. When you burn oil, you are killing any health benefits the oil could possibly provide, as well as increasing free radical and other cancer-causing compounds (3).

I find that a lot of culinary experts tend to stop there when trying to select a proper oil. This is a mistake, because each oil/fat also comes with its own composition of various fats, specifically – saturated, monounsaturated and polyunsaturated fats. As a rule, the more saturated fats present, the less likely the fats will denature or oxidize from the heat and go rancid while cooking. Monounsaturated fats have also been shown to be relatively stable during cooking at certain low temperatures and polyunsaturated fats are the worst for cooking. The reason saturated fats and monounsaturated fats are more stable during cooking is because they have less double bonds in their structure. Double bonds tend to be weaker than single bonds. A saturated fatty acid has no double bonds and monounsaturated generally will only have one double bond in their structure (hence the mono). Conversely, a polyunsaturated fatty-acid, will commonly have 2 or more double bonds, making it much more unstable to heat, light and oxidization. To add, polyunsaturated fats can come in two flavors: omega-3 fatty acids or omega-6 fatty acids. Both are necessary for healthy cellular function, but it is best to maintain about a 1:1 ratio of these fats. What you will find is many of the oils below are much higher in omega-6 fats; these result in consuming too much omega-6, which is fuel for our body’s inflammation cascade. Too much inflammation is a recipe for a many chronic health problems ranging from anything from arthritis, auto-immune conditions to cancer! (4)

The Cooking Oil List

1) Seed and Veggie Oils

At a quick glance, you may think a lot of these oils are great to cook with. They have a high smoking point, and are cheap! That’s why most restaurants will typically use these oils. These include:

  • Corn oil – primary used for salad dressings and cooking oil. When you consume non-organic versions you will be most likely exposing yourself to herbicides like roundup, and even if you consume organic, you are increasing your toxic exposure from the high amounts of mold generally found in corn.
  • Palm oil – The tropical oils has gained increased popularity among West Africa and Brazil. Most palm oil on the market is one of the large offenders for rainforest deforestation.
  • Rapeseed (Also known as Canola oil) – this is the most widely used cooking oil; most is GMO
  • Safflower oil – up until the 1960s this oil was used in paint! Now it is found in salad dressings and cooking. Yuck.
  • Soybean oil – similar to corn oil; high risk of mold exposure; most likely GMO
  • Sunflower oil – another common cooking oil. Has a high polyunsaturated profile and thus should not be used for cooking.
  • Cottonseed oil – primary used for salad dressings and cooking oil.  Has a high polyunsaturated profile and should not be used for cooking.

Unfortunately, there are a lot of problems with these oils. I would go as far as to say you are better off never using these oils – EVER. Here’s why…

  • Many of these cooking oils, specifically corn, cotton, canola and soy, are often made from GMO crops.
  • These are mostly seed oils. How do you squeeze oil out of a tiny seed? Chemical solvents are often used as the standard for oil extraction. The two main chemicals used are hexane and benzene. The problem with this process is often chemical residues remain in the oil. Benzene is a carcinogen (5) and hexane is a neurotoxin (6).
  • Although they have a high smoking point, making them a potential “ideal” cooking oil, these oils are extremely high in polyunsaturated fats, making them very unstable to heat.

2) Olive Oil

This too is considered a vegetable oil, but I wanted to put this oil into a separate category so I can go into a little more detail. Commonly used in salad dressings, cooking, cosmetics, and soaps, olive oil has a multitude of uses. When it comes to using for cooking, I don’t recommend it.

  • Even though olive oil is about 73% monounsatured fats, making it more stable than some other cooking oils on the market, its smoking point is around 320°F making it one of the more delicate oils.
  • The little polyunsaturated fats olive oil does contain is much higher in the pro-inflammatory omega-6 fats, coming out to be a 1:13 – omega 3:6, respectively.
  • Olive oil is also notorious for being fake. That’s right, it has been reported that up to 70% of the olive oil on the market have been doctored up, using cheaper oils such as canola and soy (7).

3) Avocado Oil

Fun fact: Avocado is not a vegetable; it is a fruit! This oil is commonly used in cosmetics, but it has been used by some for cooking. The reason for this is because of its high monounsaturated fat composition, making it a more heat-stable cooking oil. It also has a smoking point around  520°F, making it one of the safest oils to cook with. Sounds good right? Sort of. My biggest gripe with avocado oil is that, similar to a lot of seed oils, the way the oil is extracted is using chemical solvents, such as hexane, which I mentioned earlier is a neurotoxin. What’s more, due to lax labeling laws, companies don’t even have to specify the process for which the oil is extracted. That means you just don’t know what you’re buying. I feel it’s better to stick with the basics and just eat your avocados whole. Then you still have access to all those healthy fats as well as not having to worry about ingesting low-doses of chemical solvents.

4) Peanut Oil

Typically used in asian cooking and salad dressings, this is yet another oil I recommend to stay clear from!

  • Often contaminated with toxic mold called aflatoxins, research has found in animal studies that these toxins are linked to liver cancer (8).
  • Eating peanuts also increase gastric muc
    us production, by more than 40%, which is indicative to inflammation and general gastric-distress (9).
  • Peanuts have also been found to increase serum or  very-long chain fatty acids. These types of fats do not fit in our cell membranes and are often found in the brains of Alzheimer’s patients (10).
  • Peanuts and other legumes are also high in a plant protein lectin. Lectins can contribute to increase gut permeability which causes larger substances to pass into your bloodstream putting you at risk of developing autoimmune conditions.

5) Other types of nut oils

These include: macadamia, almond, cashew, etc. have their merits, but I don’t generally recommend for mainly the chemical processing that is often done to make these oils.

6) Fish Oil

Fish oil on its own is great; it is super high in omega-3 fatty acids, which we seem to almost never be able to get enough of. When it comes to cooking, I do not recommend using this type of oil. This is mostly due to the fact that like all high polyunsaturated oils, they are extremely prone to oxidation and rancidity.

7) Duck/Chicken Fat

As fancy as it may be to eat something with bird fat, I find the high pro-inflammatory omega-6 profile in these fats to be unfavorable. In fact, I don’t recommend poultry in general for this reason.

8) Vegetable shortening/Margarine

Used by many, these types of fats have been a favorite for some time. You may have noticed that normal vegetable oil is liquid at room temperature, but these products are solid. What gives?! Science; that’s what. Using standard vegetable oil, in combination with hydrogen and a nickel catalyst, the result is a hydrogenation process that alters the molecular structure of the fat – from a polyunsaturated into a saturated structure. The result is a no longer liquid fat, but solid at room temperature (11). Here are the reasons I do not recommend consuming these man-made fats:

  • As a result of hydrogenation, the new fatty acid structure becomes trans; meaning it becomes what is often called a trans fat. As you probably know trans fats are very rarely a good thing, as they often will add to cardiovascular risk.
  • Since these fats are made from vegetable oils, you are also consuming high omega-6 fatty acids, chemical solvents, and most likely GMOs.

… So at this point you are probably thinking, “is there any type of oil I can cook with”? Below are a few fats that I believe are much safer than a lot of the options out there, but again, still are not perfect.

9) Animal fats, ie, lard, butter, etc.

For decades we were told that the fats found in animal fat (ie, saturated fats), would increase our risk of cardiovascular disease. New research has come out to prove this is far from the truth. In fact, there has never been a study out there to accurate prove a correlation between increase saturated fat consumption and cardiovascular disease (12). So with that out of the way, don’t be fearful to use animal products as a cooking oil/fat. In fact, because of their high saturated fatty acid structure, these types of cooking oils/fats are very heat stable. The smoking point for lard is about 370°F; and for butter, about 350°F.

The only caveat I have with recommending animal products for cooking is to make sure you are choosing fats that come from grass-fed, pasture-raised animals. The reason for this is when animals are fed a grain-based diet, which is standard of most animal products – even organic for that matter – the fatty acid profile will be much more similar to vegetable oils. Meaning, they have a high pro-inflammatory omega-6 profile in the animal fat.

10) Coconut Oil

This is probably your best option. Coconut oil is about 90% saturated fat, making it extremely heat stable. It also comes with a smoking point around 350°F, which is the same as butter.  The only thing you have to watch out for is making sure you are buying organic coconut oil and getting a product that doesn’t use hexane for extractions. The difficult issue is that, as mentioned earlier, companies do not label. Choosing coconut oil labeled “unrefined,” “virgin,” or “extra-virgin” are often the safer bet if you want to avoid chemical residues. Sadly, even organic coconut oil can use hexane, so choose wisely!

11) Ghee/Clarified Butter

Ghee is a clarified butter, traditionally used in Indian-cuisine. To make it, you slowly simmer butter, which allows the separation of the milk solids and water from the butter fat. Using only the clarified butter fat, ghee has a longer shelf life and a much higher smoking point than butter – around 485 °F (13). Ghee also is extremely low lactose and casein, making it a great option for even the lactose-sensitive folks. And finally, due to its high saturated fat profile, ghee is an outstanding option for cooking. I rank ghee as my favorite cooking oil. Just make sure you only buy ghee that comes from pastured, grass-fed cows.


After choosing the right kind of cooking oil/fat and making sure you aren’t exposing yourself to extra unnecessary toxins, it is also important to store your fancy oils properly. Make sure to keep all your cooking fats/oils in a sealed, airtight container, away from sunlight and heat. Keeping your oils in your refrigerator is your best bet. If you want to maintain the oil’s room temperature structure, keep only a week’s worth of oil outside the fridge. When oils sit outside your fridge, maintain all other storage rules – airtight container, away from light and heat.

Let’s wrap it up!

In the end, when cooking your food, play it safe by avoiding high heat cooking methods such as BBQ or fried foods. Using methods such as steam, low-temp sautéing/stir-frying, or even baking below 300°F is a good way to go. If you’re sautéing or stir-frying something, it is always best to cook using only water and THEN add the desired fat or oil when you are almost finished cooking your food. The extra water helps keep the smoking point of the oil down and minimizes the risk of what I like to call “rancidification” the oil.

That’s it for now. I hope you find this guide helpful. You’re on your way to making your healthy food… well… healthy!




Hi, I’m Andy and I’m the face of OptimizedFit!
I’m a nutritionist, fitness coach, healthy-lifestyle optimizer, and all around health and fitness nerd. My job is to help you discover the cutting-edge biohacks to better optimize your life. I’m on a mission to learn and share my findings with others so we can all become better humans.

Please note: I have the right to delete comments that are offensive or off-topic.

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