What are the Worst Foods You Should Avoid for COVID-19?

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A compelling report in the journal Gastroenterology offers a radical new but logically sound explanation for why some COVID-19 patients develop life-threatening organ failure. According to the authors, the data suggest that COVID-19 mortality rates are strongly dependent on the amount of unsaturated fat consumed.

Unsaturated Fats Increase Mortality Rate

Simply put, consumption of unsaturated fats is associated with increased mortality rates from the infection. On the positive side, early treatment with low-cost calcium and egg albumin may reduce rates of organ failure and ICU admissions.

While no clinical trials of this type of therapy have been conducted, the authors believe it is time to conduct such a study, as early albumin and calcium supplementation may bind unsaturated fat and reduce damage to vital organs. They also point out that saturated fats are protective.

The most Dangerous Fat of All

I’m currently writing a book about the fat that I believe may be the leading cause of disease in the Western diet, omega-6 linoleic acid (LA). And since diet-related comorbidities account for 94% of all COVID-19-related deaths, controlling your diet is a simple, common-sense strategy to reduce the risks associated with this infection.

LA accounts for the majority – about 90% – of omega-6 fatty acids consumed and is the leading cause of nearly all chronic diseases. Although it is an essential fat, LA acts like a metabolic toxin when consumed in excess.

This is because polyunsaturated fats like LA are highly susceptible to oxidation. When the fat oxidizes, it breaks down into harmful subcomponents such as advanced lipid oxidation end products (ALES) and OXLAMS (oxidized LA metabolites). These ALES and OXLAMS are the real culprits of the damage.

One type of advanced lipid oxidation end product (ALE) is 4HNE, a mutagen known to cause DNA damage. Studies have shown that there is a clear link between elevated levels of 4HNE and heart failure.

LA is broken down to 4HNE even faster when the oil is heated, which is why cardiologists recommend avoiding fried foods. LA intake and the resulting ALES and OXLAMS also play an important role in cancer. HNE and other ALES are extraordinarily harmful even in very small amounts.

While excess sugar is certainly bad for health and should generally be limited to 25 grams per day or less, it does not cause a fraction of the oxidative damage that LA does.

Processed vegetable oils are a major source of LA, but even foods lauded for their health benefits contain LA and can be a problem if consumed in excess. Examples include olive oil and conventionally raised chickens fed LA-rich grains.

Many now know that the ratio of omega-6 to omega-3 is very important and should be about 1:1 or even up to 4:1, but simply increasing omega-3 intake cannot offset the damage that excess LA causes. You really need to minimize omega-6 intake to avoid damage.

LA Damages Your Mitochondria

To understand how excessive consumption of LA damages your metabolism and impairs your body’s ability to produce energy in your mitochondria, we need to do some molecular biology. There is a specific fat that is only found in your mitochondria – most of it is in the inner mitochondrial membrane – called cardiolipin.

Cardiolipin is made up of four fatty acids, unlike triglycerides, which contain three fatty acids, but the individual fats can vary. Examples include LA, palmitic acid, and the fatty acids DHA and EPA found in fish oil. Each of these fatty acids has a different effect on mitochondrial function, and depending on the organ, mitochondria work better with certain fatty acids.

For example, your heart prefers to build cardiolipin with LA, while your brain dislikes LA and prefers to build cardiolipin in the mitochondria with fats like DHA. As mentioned earlier, LA is very susceptible to oxidation.

The LA in mitochondrial cardiolipin is exposed to iron-containing cytochromes in the electron transport chain, which in turn can catalyze oxidation of cardiolipin. This is bad news because oxidation of cardiolipin is one of the factors that control autophagy.

In other words, oxidation of cardiolipin is one of the signals the body uses to signal that something is wrong with a cell and to trigger the destruction of that cell, a process called apoptosis. Your cells know they are broken when they have too many damaged mitochondria, and the process that controls this is largely the oxidation of the omega-6 fats contained in cardiolipin.

So if you change the composition of cell membranes and fatty acids stored in cells toward a higher proportion of omega-6 fatty acids, you make your cardiolipin much more susceptible to oxidative damage. The good news is that the composition of fatty acids in both cell membranes and cardiolipin can be changed in a favorable direction by making some specific changes in your diet.

Fat intake associated with COVID-19 Results

Returning to the question of how fat intake may affect COVID-19 outcomes, the Gastroenterology publication notes that unsaturated fats “cause injury [and] organ failure that resembles COVID-19.” More specifically, unsaturated fats are known to cause lipotoxic acute pancreatitis, and the sepsis and multisystem organ failure that occur in severe cases of COVID-19 closely resemble this condition.

Their proposed solution, early supplementation with ovalbumin and calcium, is likely to be helpful because these substances are known to bind unsaturated fats, thereby reducing organ damage. The two diseases also share other risk factors.

As explained in the Paper:

Unsaturated fatty acids (UFAs) produced by lipolysis of adipose tissue cause multisystem organ failure, including acute lung injury. Severe acute pancreatitis and severe COVID-19 share obesity as a risk factor, along with lipase elevation, hypoalbuminemia, and hypocalcemia.

The authors go on to explain that the ACE2 receptor, which the SARS-CoV-2 virus uses to invade your cells, is located on fat cells, and that oleic acid – an omega-9 monounsaturated fat found in olive oil – has been shown to cause multisystem organ failure, including acute lung injury.

PUFAs also generally depolarize mitochondria and increase inflammatory mediators. All of this led researchers to investigate the possible link between lipotoxicity (toxicity caused by harmful fats such as LA) and severe COVID-19 leading to organ failure.

The study includes an interesting diagram summarizing the investigative approach the researchers used to conclude that unsaturated fat intake correlates with COVID-19 outcomes, which unfortunately I cannot reproduce here. In summary, however, it appears that a higher intake of polyunsaturated fats (PUFAs), especially LA, leads to a higher risk of severe COVID-19, whereas a higher intake of saturated fats lowers the risk.

dietary saturated fat intake1

dietary unsaturated fat intake2
Saturated fat intake (kg/capita/year) was negatively and unsaturated fat intake was positively associated with [COVID-19] mortality. ~ Gastroenterology September 2020

PUFAs increase COVID-19 Mortality, While Saturated Fats Decrease It

The researchers discovered that hypocalcemia (below-average calcium levels in blood or plasma) and hypoalbuminemia (low albumin levels in blood) were seen early in patients with severe COVID-19.

In examining data from COVID-19 patients, they also found that low arterial partial pressure of oxygen and low oxygen ratio are associated with higher levels of unbound fatty acids in the blood. They also speculate that UFAs may cause vascular leakage, inflammatory damage, and cardiac arrhythmias in severe COVID-19 disease.

In tests on mice, animals given LA developed a number of conditions similar to fatal COVID-19, including hypoalbuminemia, leukopenia (low white blood cell count), lymphopenia (low lymphocyte count), lymphocyte injury, thrombocytopenia (low platelet count), hypercytokinemia (cytokine storm), shock, and kidney failure.

How to calculate your LA intake with the Cronometer

Considering the damage LA causes, it is not surprising that it could play an important role in COVID-19. As mentioned earlier, virtually all comorbidities associated with COVID-19 are diet-related, share many of the same risk factors, and can be triggered or exacerbated by high LA intake.

Fortunately, you don’t have to spend hundreds of dollars to have your food analyzed for LA. All you have to do is accurately enter your food intake into Cronometer – a free online nutrition program – and you’ll get your total LA intake. The key to accurate entry is carefully weighing your food with a digital kitchen scale so you can enter the weight of your food to the gram.

Cronometer.com is free to use if you use the desktop version. If you feel the need to enter your data via your cell phone (which is not recommended), you will need to purchase a subscription. Personally, I have been using the desktop version exclusively for the past five years, as it has a greater feature set and allows me to avoid the electromagnetic fields from my cell phone.

It is best to enter your food the day before you actually eat it. The reason for this is simple: it’s impossible to delete the foods if you’ve already eaten them, but you can easily remove them from the menu if you find that something exceeds the ideal limit.

Once you’ve entered the foods for the day, go to the “Lipids” section on the lower left side of the app. The image below is from one of my recent data entries and shows you what the section looks like. To find out how much LA is in your diet that day, you just need to see how many grams of omega-6 are in it. About 90% of the omega-6 you are consuming is LA.


To determine the percentage of omega-6/LA in your diet, go to the “Calorie Summary” section shown in the figure below. In my case, I ate 3,887 calories. Since there are nine calories per gram of fat, you need to multiply the number of omega-6 grams by nine to get the total amount of omega-6 calories. In my case, that’s 69.3 calories.

Next, divide the LA calories by your total calories. In this example, that would be 69.3/3887 = 0.0178. If you multiply that number by 100, or move the decimal point two places to the left, you get the percentage in a whole number. In my example, it is 1.8% of the LA. This is within the ideal LA percentage, which is between 1% and 2% of total caloric intake.

Cronometer is in the process of automatically displaying the “percentage of omega-6” in your diet, but that won’t be implemented until early 2021.

calories summary

Helpful Feature You May Not Be Aware Of Yet

Most people are unaware of an incredibly helpful feature in Cronometer that allows you to easily determine where your total LA content comes from. If you hover your mouse over the percentage box next to the omega-6 value, a pop-up window will appear that ranks foods by their LA content.

In my case, you can see below that the four eggs I ate are my biggest LA source. Eggs are a very healthy food, but unfortunately almost all chickens, even those raised on pasture, are fed grains that are high in LA. Even if the grains are organic, they still contain LA.

I raise my own chickens and am currently doing an experiment to change this by feeding my chickens a very low LA, grain-free diet. I will have the eggs analyzed at a research lab and hope to reduce the LA content by 90%, hopefully bringing my LA intake below 5 grams.

Interestingly, my analysis shows that my main protein, bison, contains only 0.5 grams of LA, even though I ate 8 ounces of it that day. Fruit is also mostly LA-free, making it a better source of healthy carbohydrates than grains.

On my high-carb days, I also eat rice, in this case about 100 grams of carbs a day, and the rice contains no LA. Both rice and millet are two of the best grains because they do not contain gluten. Rice, however, has the added benefit of being LA-free. It is best to use white rice, as the fiber in brown rice has little nutritional value and can even cause problems.


Carbohydrates – Choose Wisely

I have to admit that I am biased in this area because my first book in 2004 (which was a New York Times bestseller) was called “The No Grain Diet.” The concern about not eating grains was based primarily on the overconsumption of carbohydrates, which could lead to insulin resistance. At the time, I didn’t realize that increased LA consumption was probably a much bigger problem than excessive carbohydrate consumption and that most grains are usually fortified with LA.

However, if you increase carbohydrate intake in the form of sugar and processed wheat, and then add seed oils, you have the devil’s triad, which together contribute to most metabolic diseases.

Although I wrote the book 17 years ago, I still believe that most grains should be avoided or at least kept to a minimum because they are usually high in carbohydrates and LA. Many are also loaded with other problems such as gluten, oxalates and phytates.

In my book, Fat for Fuel, I advocate the cyclical use of balanced and healthy carbohydrates in the form of fruit and healthier grains. For most of us, fruit is a far healthier option than grains because there is virtually no LA in fruit, with exceptions like avocado, which is technically a fruit.

Metabolic Flexibility is the Key to Optimal Health

About 90% of the population is insulin resistant. Ideally, you should first flex your metabolism and improve your ability to burn fat as your main fuel. I discuss this strategy in detail in “Fat as Fuel.” It usually takes a few weeks to months for someone to transition into a state of metabolic flexibility.

If you are metabolically flexible, you usually have normal blood pressure, are not overweight, and have a fasting blood glucose level below 90 that you can easily measure at home.

While limiting carbohydrates to less than 50 grams per day in a metabolically flexible state is an effective strategy, once most people regain their ability to burn fat for fuel, they will find that they need to add a healthy source of carbohydrates back into their diet. A simple strategy is to consume about 50 grams on low-carb days and double or triple that amount on high-carb days.

You can start by simply alternating low-carbohydrate and high-carbohydrate days and monitoring your fasting blood glucose. If it rises over time, you’ll know it’s probably better to reduce the frequency of high-carbohydrate days. Again, fruit or white rice are the best carbs because they are virtually LA-free. If you have been on a low-carb diet for a year or two, you can use other carbohydrates with higher LA content.

Fats – be Careful with Cooking Oils

Ideally, you should limit the amount of oil you use for cooking. As a rule, it is better to cook without oil and use pastured butter instead. This is because seed oils are the largest source of omega-6 LA, and the higher you heat food, the more toxic byproducts are created.

You may be wondering how to limit your cooking oils. Let me give you an example. If you are preparing ground beef or bison, you can cook it in a skillet or covered pot at low heat by turning the water in the meat into steam and cooking the food at a low 212 degrees Fahrenheit.

If you decide to use oil for cooking, you can use the chart below to help you choose the best oils. It is color-coded for your reference. The preferred oils are shaded green. Note that beef tallow or butter from concentrated animal feeding operations (CAFO) contains three times as much LA as the grass-fed version. The levels are still very low and within an acceptable range, but it is clearly better to choose the higher quality grass-fed version if you can.

Lard and palm oil are less suitable because of their higher LA content. However, there is a lot of confusion around olive oil that needs to be cleared up. Avocado oil, while not very popular, has the same issues as olive oil.

The LA content of both olive oil and avocado oil is very different. Usually it averages around 10%, although some oils can be twice that. The reason you have to be extra careful when using these oils is that the vast majority (over 80%) are adulterated with cheaper high LA oils like safflower oil.

So if you are going to use one of these oils, you need independent, objective confirmation that the oil has not been tampered with. These brands tend to be more expensive, as the production costs for real olive and avocado oils are much higher.

Oils to avoid at all costs are the main culprits in the destruction of health in the 20th century: the toxic seed oils, marked in red. However, the dose makes the poison. So, in theory, you can use any of the oils in the table below as long as your total LA intake that day is less than 2% of your total calories. The higher up the chart the oil is, the more likely you are to exceed your safe limit for that day.

cooking oils

What about Seeds and Nuts?

Seeds and nuts can be used in moderation. The table below shows how much LA is in seeds and nuts. You can see that most contain almost half LA. Because of this, it is very easy to get really high LA levels if you eat a lot of seeds and nuts, with the exception of macadamia nuts.


Also remember that even if a nut has a relatively low LA content, like almonds, it can be loaded with other potential problems like oxalates. Oxalates are razor-sharp crystals found in many nuts and seeds. They are water soluble and are only found in the unprocessed seeds or nuts. If you consume an oil version of the seed or nut, it will contain virtually no oxalates.

So the most important thing to remember is that seeds and nuts are clearly allowed, but large amounts should be avoided. Be sure to enter them into Cronometer so you can see exactly how much LA they contain and how they affect your total daily intake.

Please note that the percentage of LA listed for the above foods is a typical average. It is important to understand that the percentage of LA in a given food can vary greatly due to many factors. However, the values listed are what is typically found in the literature.

Ideal Protein Sources

In general, animal foods have much lower LA content than plant sources. This is especially true for seeds and most nuts, with the exception of macadamia, as you can see in the table above. In addition, many plant sources contain oxalates, phytates and gluten, the adverse health effects of which are already well documented.

However, there are two important exceptions. Ideally, you should limit your consumption of chicken and pork, as these animals are usually fed grains that are contaminated with LA. The LA content in these animals is usually between 10 and 20%. They contain lower levels of LA if not raised in a confined animal feeding operation (CAFO), but most likely exceed levels in lamb, beef, bison and other wild animals such as elk by a factor of 10.

For most of us, the ideal protein source would be bison, followed by beef and lamb. An 8 ounce serving of these foods typically contains less than 1 gram of LA. In addition to eating muscle meat, organ meats should be consumed regularly as they are fortified with important micronutrients not found in muscle meat.

Eggs are another LA source of concern, as egg yolks contain about 16% LA. This is because almost all chickens, even those raised on pasture, are fed grain as their main feed. As long as you are not allergic to eggs, they are an incredibly healthy, nutrient-dense food and one of the best sources of bioavailable choline.

I think it is advisable to limit your consumption of eggs to four or less per day, as this would provide about 2.5 grams of LA. As mentioned earlier, I am currently in the middle of an experiment.

I am feeding my 20 chickens a low LA carnivore-like diet consisting of a gallon of 4-day-old sprouted mung beans with 4 ounces of melted butter, along with a regular supply of beef liver and mealworms. I will be testing the eggs for LA over the next few months as it takes some time for LA to be released after consumption.


1. Gastroenterology 2020 Sep; 159(3): 1015–1018.e4

2. CDC.gov August 26, 2020

3. Chempro Fatty Acid Composition of Oils and Fats

4. Weston A Price Fatty Acid Analysis of Grass-fed and Grain-fed Beef Tallow

5. Journal of the American Oil Chemists‘ Society. 72 (9): 1079–1081

6. Li, D., & Hu, X. (2011). Fatty Acid Content of Commonly Available Nuts and Seeds. Nuts and Seeds in Health and Disease Prevention, 35–42

7. British Journal of Nutrition 96 Suppl 2(S2): S29-35

8. The Paleo Diet Seed Fatty Acid Composition