Fasting and the Ketogenic Diet for COVID-19

We have discussed various factors that help to support the body in the face of a viral illness. Now, we would like to dive into the area of dietary interventions for any viral illness. While these strategies can be enormously beneficial for those struggling with any virus, we will also highlight a recent study on the diet most useful for combatting COVID-19.


Metabolism and Viruses

The body was designed to run on two different energy sources: sugar and fat. Any time blood glucose elevates from eating, stress, or lack of sleep, the body uses sugar as its main energy source. This is known as a glycolytic state. Conversely, when the body is in a fasted state or when we intentionally eat low carbohydrate, high-fat meals, our metabolism shifts to a fat-burning ketogenic state due to the absence of sugars in the bloodstream. Our bodies were designed to go in and out of sugar and fat burning states at different times of the day. We like to refer to this as metabolic flexibility. In fact, the body seems to thrive when in a fat-burning, ketogenic metabolic state. 

Sugars are the Ideal Fuel Source for Viruses

Interestingly, switching the host metabolism from a sugar burning state to a fat burning state has been shown to slow the replication of viruses. Viruses do not have their own energy source. When they inhabit a host, they must rely on the host's energy and metabolic function. When the host consumes a diet high in processed foods, carbohydrates, and sugars, the body is in a sugar burning state. In this state, viruses of various kinds are able to replicate very quickly because of the widely available sugar fuel source.

Sugars are the Ideal Camouflage for Viruses

Not only does being in a sugar-burning state provide viruses with plenty of energy to replicate quickly, sugars can also camouflage the virus and protect it from an immune system attack. Many viruses, including COVID-19, essentially coat themselves in sugar in order to replicate. When the virus does this, it not only fuels itself with the sugar, but also camouflages itself from the immune system when it is encased in a sugary coating called glycans. This process is known as viral glycosylation.

COVID-19 takes over the host’s cellular machinery to surround itself in glycans. The surface protein on the virus that allows it to bind to and enter human cells is completely covered by these sugars. SARS-CoV-2 uses an extensively glycosylated spike protein that protrudes from the viral surface to bind to angiotensin-converting enzyme 2 (ACE2) to mediate host-cell entry. Essentially, this glycan shield camouflages the virus as “self” to hide it from the immune system. The coronavirus tricks its way into the cell like a “wolf in sheep’s clothing.” 

COVID-19 is not the only virus to use glycans for replication and disguise. Other viruses including influenza, HIV, Hepatitis C, West Nile Virus, SARS-CoV-1, and Ebola also go through viral glycosylation. 

Comorbidities

Unfortunately, there is a growing body of evidence that shows individuals with comorbid conditions are much more at risk for a serious viral illness, including COVID-19. Some of these comorbidities include diabetes, metabolic syndrome, obesity, hypertension, cardiovascular disease, and asthma. Many of these conditions are rooted in the host’s metabolism being in a suboptimal, immune-damaging state as it is constantly hopped up on sugar. This allows viruses and other pathogens to be able to replicate rapidly and take a greater hold on the host who has metabolic dysfunction.

Dietary Strategies to Beat Viruses

Avoid Detrimental Fats

It is important to understand that consuming highly-refined industrial seed oils not only contributes to inflammation and a weakened immune system, but they also foster an environment where the host is more susceptible to viral infection. Industrial seed oils actually make the cell more inviting to viral infections. When these oils are consumed, the balance of fatty acids that coat the cell and makeup the cell membrane are changed. The presence of these detrimental fatty acids actually helps viruses to easily enter and take hold of the host’s cells. Furthermore, consuming these fats contributes to insulin resistance, perpetuating blood sugar dysregulation. This also prevents the body from burning fat for energy and being in a state of ketosis.

Harmful Fats to Avoid:

  • Canola oil

  • Corn oil

  • Cottonseed oil

  • Rice bran oil

  • Safflower oil

  • Sunflower oil

  • Soybean oil


Consume Health-Promoting Fats

Emphasizing certain fats can not only nourish our cells, but they can also help shift the body into a ketogenic state. Medium chain triglycerides are made up of fewer carbon atoms than long chain fatty acids and are found in coconut oil, palm oil, and quality dairy products. Unlike long chain fatty acids, MCTs are processed quickly by the liver and are used for energy or turned directly into ketones. The presence of ketones in the blood promotes the fat-burning state of ketosis (not to be confused with diabetic ketoacidosis). Not only do MCTs help promote ketosis, they also increase energy and endurance, improve brain function, aid in weight loss, lower cholesterol, and  balance blood sugar levels. When looking at MCTs from a viral standpoint, the lauric acid present in MCTs has been shown to repress the viral envelope formation and slow viral replication. 

Medium Chain Triglycerides (MCTs) are found in:

  • Cream from grass-fed animals

  • Ghee from grass-fed animals

  • Butter from grass-fed animals

  • Coconut oil

  • MCT oil

Switch Your Metabolism Through a Ketogenic Diet


As we discussed, there are two main fuel sources for our bodies-sugar and fat. The body is designed to maneuver easily in and out of each of these metabolic states. As mentioned earlier, the ease in which the body shifts between these two metabolic states is metabolic flexibility. The body does best when it is in fat-burning ketosis for about 70-75% of the time and in a sugar burning state 20-25% of the time. 

The ketogenic diet focuses on quality dietary fats as the main fuel source for the body. Usually the breakdown is 60-70 percent of your nutritional calories coming from a fat source. The rest of calories come from proteins and carbohydrates. To foster this metabolic state on an even deeper level, decreasing carbohydrate intake and increasing the fasting window are helpful. When these ideal macronutrient ratios are in place, it forces the body into a fat-burning, ketogenic state. This metabolic state challenges the body so that it is forced to be in a healthier place. When we follow up this state of metabolic challenge with eating, rest, and sleeping, our bodies are able to recover and grow more resilient.

What is the Ideal COVID diet?

Again, when we are in a fat burning, ketogenic state, we do not give the virus a fuel source. This will slow the viral replication. One particular study that highlights this looked at individuals fasting for Ramadan. These people consumed a protein and fat-rich breakfast that included 20 grams of MCTs. For lunch, they consumed 20 grams of MCT and continued their fast for a total of 8-12 hours. This increase in medium chain triglycerides during their fasting window promoted ketogenic metabolic pathways and slowed viral replication. Dinner was a nutrient-dense meal that included a variety of fruits and vegetables.

The study showed that fostering a ketogenic state for part of the day, intermittent fasting, and focusing on MCTs and nutrient-dense foods offer prophylactic and adjuvant treatment strategies for those combatting SARS-CoV-2. Whether you hope to avoid succumbing to a viral infection, are currently suffering from COVID-19 or another acute virus, or are suffering from “Long-Haulers Syndrome”, putting some of these dietary practices in place will greatly support blood sugar regulation and immune function. 

Ashley Turner