Will Eating Keto Help Prevent Flu?

The flu virus is more commonly diagnosed during the fall and winter months, although it’s detectable year-round in the U.S.¹ While the exact duration may vary, most activity begins in October, peaks in January and February and caps as late as May.

During this “season,” other respiratory viruses are also prevalent, and may cause flu-like illnesses such as rhinovirus and respiratory syncytial virus. When it comes to treating it, the flu virus is not a bacterium and thus is not affected by antibiotics. The illness is contagious and may result in mild to severe illness. It’s an airborne disease that spreads through air droplets expelled when infected people cough, sneeze or simply open their mouths and talk.²

In 2018, the CDC found that, on average, 8% of the U.S. population suffers with the flu during flu season. Those most likely to get it are children; seniors are the least likely to get sick.

An infection with influenza virus is different from one triggered by cold viruses.³ Symptoms are usually sudden and often include fever, muscle and body aches, headache, fatigue and a cough or sore throat. However, as reported by the CDC, not everyone who gets flu will develop a fever.

Eating Keto May Protect You Against Influenza

A team from the Yale School of Medicine discovered that mice with gout that were fed a keto diet experienced reduced levels of inflammation.⁴ The team theorized the diet could have a similar effect on humans who get flu. This is important because influenza has a history of severely damaging the lungs.

The team tested the theory in a small animal model study⁵ during which they fed the intervention group of mice a high fat, low-carbohydrate ketogenic diet and the control group a standard diet.⁶ Both groups were then infected with virulent influenza A. The researchers found that after four days all the mice fed the standard diet were infected, as compared to 50% of the mice on the keto diet.

The mice eating a keto diet who did get infected did not lose as much weight — a sign of flu infection in animals. The researchers found the mice eating a ketogenic diet had an immune response that promoted the expansion of gamma-delta T cells in the lungs.⁷

In another stage of the study, the researchers used mice genetically altered to not produce gamma-delta T cells to confirm the functional importance of the specialty cells in protecting the lungs against infection. The results suggested gamma-delta T cells raise the barrier function in the lungs.

The gamma-delta T cells line the lungs and increase mucus production, which is important for protection as it traps the virus and keeps it from spreading.⁸ The researchers also found a ketogenic diet demonstrated enhanced antiviral resistance and concluded it could assist with preventing flu or alleviating the symptoms.⁹

They then questioned if it was the ketones, the high fat or reduced carbs in the ketogenic diet that affected the immune system of the mice.¹⁰ They performed two additional tests in which the mice consumed ketones in a drink or a high fat high carbohydrate diet.

Data revealed the drink had no effect, while the diet produced greater numbers of gamma-delta T cells but did not increase protection against the virus. From these results it appears each factor of a ketogenic diet is necessary to boost gamma-delta T cell production and the ability to protect against the virus.

Please note: While at least one of the study’s authors told news media that getting vaccinated against influenza is the optimal thing to do, actually there are other, better ways of fighting flu than depending on a shot, which I’ll describe later in this article.

What Does It Mean to Eat Keto?

As a rising number of people deal with chronic diseases, it’s becoming increasingly evident that what you eat is a main factor in your well-being. The standard American diet often consists of excessive protein, processed grains and carbohydrates, and refined, added sugars. Indulging in this type of diet leads to insulin and leptin resistance.

As a result, you increase your potential risk of gaining weight, developing chronic inflammation and becoming prone to mitochondrial and cellular damage. By switching to eating a ketogenic diet, you reduce your risks and improve your overall health.

To follow a standard ketogenic nutritional plan, you focus on consuming high amounts of healthy fats. Aim for 70% to 85% of your total calories from healthy fats and 1 gram of protein for every kilogram of your lean body mass. Your net carbohydrates should account for no more than 4% to 10% of your daily calories.

Since energy requirements will vary from person to person depending upon daily physical activities, there is no set limit to the amount of fat you may eat. Most calories need to come from fats, and you still need to limit carbohydrates and protein for this to be a standard ketogenic diet.

Cyclical Keto Offers Greater Flexibility and Benefits

By using a cyclical approach to eating a ketogenic diet you increase the health benefits of the diet and have greater flexibility in your meal planning. There is a three-part key to using this approach: 1) restrict net carbohydrates (total carbs minus fiber) to 20 to 50 grams per day; 2) consume 50% to 85% of your daily calories from healthy fat; and 3) limit protein to one-half gram of protein per pound of lean body mass.

You may have vegetables without restriction as they are loaded with fiber and help offset carbohydrates. Cut out carbohydrates from grains and all forms of sugar, including high fructose fruit. Add healthy sources of fat including avocados, coconut oil, animal-based omega-3 from fatty fish, butter, seeds, olives and olive oil.

Macadamia nuts and pecans are ideal as they're high in healthy fat but low in protein. Organic, pastured egg yolks and grass fed animal products, along with MCT oil and raw cacao butter may all be included on your list of healthy fats. Avoid all trans fats and vegetable oils as they cause more damage than excess carbs.

It is important to maintain these ratios until your body is burning fat for fuel. Use keto testing strips to confirm you are in ketosis and keep in mind it may take a couple of weeks to a few months until your body is effectively burning fat.

Since too many net carbs prevent ketosis, use measuring and tracking tools such as a kitchen scale, measuring cups and nutrient tracker to be sure you're staying within limits. Once your body is effectively burning fat and you're in ketosis, begin cycling in and out by eating a higher number of net carbs once or twice a week.

On your high-carb days, triple the amount of net carbs to maximize the biological benefit of cellular regeneration and renewal. However, I caution you to choose healthy alternatives such as digestive-resistant starches, and forgo the potato chips and bagels.

To learn more about how potatoes, rice, bread and pasta are more digestive-resistant when they’re cooked, cooled and then reheated, see “This Simple Trick Can Minimize Damage From Unhealthy Carbs.”

A Ketogenic Diet Does More Than Help With Weight

Many report higher levels of energy and an easier time losing or maintaining their weight while eating keto. These benefits may be the result of how ketosis supports your mitochondrial health and reduces inflammation. As your body burns fat for fuel, the liver creates ketones, creating far less reactive oxygen species and secondary free radicals.

This then reduces the damage to your cellular and mitochondrial membranes, protein and DNA. This reduction in inflammation may also play a major role in chronic pain, including orthopedic conditions like osteoarthritis. One study found a ketogenic diet may reduce neuropathic and inflammatory pain.

As many of the aging factors are characterized by low-grade inflammation, eating a ketogenic diet may also reduce your risk of premature aging. The anti-inflammatory effect on the central nervous system has had an impressive effect on epilepsy and other neurological disorders. One of those is protection against Alzheimer's disease, associated with loss of language, memory and attention.

Scientists have also demonstrated the positive effect ketosis has on those who have experienced a traumatic brain injury, who have had an ischemic stroke or who have autism. In animal studies, those fed a ketogenic diet for 16 weeks demonstrated increases in cerebral blood flow and an increased abundance of beneficial gut microbiota and reduced blood glucose levels.

Insulin resistance and hyperinsulinemia are key drivers in chronic disease, including high blood pressure and atherosclerosis. Other adverse effects that occur with insulin resistance may include heart disease, cancer, diabetes and Alzheimer's disease. By improving insulin sensitivity, a ketogenic diet helps to reduce your potential risk for developing these conditions and reduces the physiological effects.

Insulin also activates the mammalian target of rapamycin (mTOR). This is an important pathway to control autophagy, your body's natural cleanup process to destroy and eliminate old damaged cells and replace them with healthy ones. This plays a significant role in aging and the development of cancer.

To slow aging and reduce your risk of cancer, you want to inhibit mTOR to activate autophagy and recycle proteins. It is important to note insulin levels activate the mTOR pathway to a greater degree than excess protein.

Natural Protection Against Flu Without Side Effects

You can boost the health effects of a cyclical ketogenic diet, including supporting your immune system, by combining it with intermittent fasting as described in my article, “How to Make Fasting Easier, Safer and More Effective.” Conversely, as I mentioned earlier, there are reasons why you may want to steer clear of the flu vaccine.

According to CDC data updated in November 2019,¹¹ the overall adjusted effectiveness rates of the 2018-2019 flu vaccine against influenza A or B viruses were abysmal at best:

Besides that, those who get vaccinated can still spread the influenza virus to others, with those who are vaccinated for two seasons in a row shedding a greater load of influenza A virus. According to a 2014 Cochrane meta-analysis, to avoid a single case of influenza 71 people must be vaccinated. 

The vaccine also increases your risk of contracting other more serious infections. It also does not work well if you take statin drugs and is associated with permanent disability, such as paralysis from Guillain-Barre syndrome. Receiving vaccinations also compromises your natural immunity, which may lead to other adverse health effects.

So what can you do to protect yourself from flu? The answer is to begin immediately by using nutrition and sun exposure to boost your immune system. Nutrition is a vital component to maintaining and gaining a healthy immune system. This includes foods high in vitamins and minerals, especially vitamin D3, which you get through daily sun exposure or, if you live in an area where that isn’t possible every day, through proper supplementation.

Before beginning any supplementation program, though, be sure to check your vitamin D levels so you know how much you need to maintain good, immune-protective numbers. You should do this twice a year, and supplement accordingly if the numbers warrant it.

GrassrootsHealth has a helpful calculator that can help estimate the dose required to reach healthy vitamin D levels based upon your measured starting point. The optimal level you’re looking for is between 60 and 80 ng/ml, and for all-around health, you’ll want to maintain this level year-round.

For other nutrition and food ideas to help naturally reduce your risk of getting sick this flu season, see my article, “Top Tips To Boost Your Immunity.”