Metabolic Inflexibility Is Key Risk Factor for COVID-19

Lifestyle factors that are within our control double and triple the risk of a fatal COVID infection
November 9, 2020 Updated: November 14, 2020

While SARS-CoV-2 is a rampant virus that can cause severe problems in vulnerable individuals, the real pandemic—the underlying cause that makes people susceptible to complications from the infection in the first place—is poor metabolic health.

Metabolism is the sum total of all the chemical reactions the body uses to maintain a living state. It has two major types: when our body breaks down molecules in the food we eat to provide cells with energy, and when our body synthesizes all the compounds needed by our cells.

Metabolic flexibility is key to our overall well-being. This refers to our body’s ability to adapt to different demands, such as changes in temperature or when we need our metabolism to ramp up while exercising.

When we feed our body problem foods, we undermine all the chemical reactions that make up our metabolism. This can end up undermining our overall metabolic flexibility. Diabetes is an example of metabolic inflexibility, a lack of ability for the body to deal with different energy demands and process food into energy properly.

Type 2 diabetes (insulin resistance) and obesity are two conditions that are almost entirely affected by lifestyle and are also two of the major factors associated with worse COVID-19 outcomes. Obesity has been identified as one of the primary risk factors for being hospitalized with COVID-19—doubling the risk of hospitalization in patients under the age of 60 in one study.

Dr. Aseem Malhotra, a British cardiologist and author of “The 21-Day Immunity Plan,” explains the role insulin resistance plays in the COVID-19 pandemic.“The real pandemic is poor metabolic health, or metabolic inflexibility,” Malhotra says. “I had become aware, as early on as March, when we were getting data from China and Italy, that there was a clear link between conditions related to excess body fat, in simple terms defined as poor metabolic health, [and] worse outcomes from COVID-19.

“We’re talking about conditions like Type 2 diabetes, high blood pressure, heart disease and, of course, obesity. And that data kept emerging. That link was so clear, and it wasn’t just out of the blue.”

Malhotra says after two decades as a practicing doctor, it is clear to him and others that people with poor metabolic health have worse outcomes from any infection. “COVID-19 has highlighted it more, and made us think about it more,” he said.

And although the data is clear, that information doesn’t seem to be making its way to public awareness.

“I was looking at that data and thought, ‘There’s something missing out of this mainstream conversation.’ [COVID] was getting a lot of immediate coverage across the world, in the UK, in the United States, but no one was talking about lifestyle.”

Obesity Is a Significant COVID-19 Risk Factor

Aside from old age, obesity has been identified as one of the primary risk factors for being hospitalized with COVID-19—doubling the risk of hospitalization in patients under the age of 60 in one study1—even if the individual has no other obesity-related health problems. A French study also found obese patients treated for COVID-19 were more likely to require mechanical ventilation.

One hypothesis for why obesity is worsening COVID-19 has to do with the fact that obesity causes chronic inflammation. The body uses inflammation to fight disease and heal itself, but when this reaction goes awry, it becomes a major contributor to disease. Chronic inflammation can lead to having more proinflammatory cytokines in circulation, which then increases your risk of experiencing a cytokine storm.

A cytokine storm response is typically the reason why people die from infections, be it the seasonal flu, Ebola, urinary tract infection, or COVID-19. Obesity also makes you more vulnerable to infectious diseases by lowering your immune function.

Insulin Resistance Augments Infection Risks

Obesity is often rooted in insulin resistance, brought on by a flawed diet. Insulin resistance is another top risk factor for COVID-19 that worsens outcomes and increases your risk of death. An April 15 article in The Scientist reviews evidence showing how higher blood glucose levels impact viral replication and the development of cytokine storms.

While the research in question looked at influenza A-induced cytokine storms, these findings may well be applicable in COVID-19 as well. In a Science Advances press release, co-author Shi Liu said:

“We believe that glucose metabolism contributes to various COVID-19 outcomes since both influenza and COVID-19 can induce a cytokine storm, and since COVID-19 patients with diabetes have shown higher mortality.”

COVID-19 Risk Factors Can Be Rapidly Ameliorated

The good news, as Malhotra stresses, is that the lifestyle factors that make you more prone to severe COVID-19 infection and death can be modified and ameliorated in as little as 21 days, simply by changing your diet. Like me, Malhotra feels this has been sorely missing from pandemic response messaging.

“They should have been saying, ‘Listen, there’s no better time for you to really think about trying to improve your health and looking into what you eat, [get] moderate exercise, sleep, all those things,” Malhotra says. “But it wasn’t happening.”

To fill the information gap, Malhotra began writing. Initially, he wrote a series of articles for British newspapers. He also got the opportunity to speak about this on Sky News.

“I made it very clear. I said, ‘Listen, there’s a chance at some point we’re all going to get this virus, and we want to make sure that we’re in the best position to be able to deal with it, so that we don’t get sick from it when it happens.’”

“I think I was probably, maybe, the only doctor who had the opportunity to say that in a mainstream media, probably in the world, at that time; I think no one else had said it.”

As more data became available, Malhotra’s writings turned into “The 21-Day Immunity Plan.” Malhotra also had the opportunity to share information with the United Kingdom’s Secretary of State for Health, Matt Hancock. By the time the book was finished, Prime Minister Boris Johnson came out saying something needs to be done, on a policy level, about the obesity epidemic.

That said, we don’t have to have government policies in place to personally implement these lifestyle strategies. The information is available. It’s well-documented, noncontroversial, and relatively simple to do. Surprisingly, Malhotra’s message has been largely well-received, and hasn’t been censored to the extent that many others have.

Unfortunately, we’re still fighting against a tsunami of dietary misinformation and false advertising on a daily basis, which makes it difficult to really get this message out and make it stick. “If every day the government was putting out a message saying, ‘Metabolic health is the key,’ then we would have a really big impact,” Malhotra says.

Most People Have Poor Metabolic Health

The central thesis of Malhotra’s book is that we have a pandemic of metabolic inflexibility or metabolic ill health. There are five primary parameters of metabolic ill health, which include having:

  1. A large waist circumference
  2. Prediabetes or Type 2 diabetes
  3. Prehypertension or hypertension (high blood pressure)
  4. High blood triglycerides
  5. Low HDL cholesterol

If you have all of those five parameters within the normal ranges, you are in good metabolic health. Having three or more abnormal parameters is indicative of metabolic syndrome. Metabolic inflexibility can further be divided into two primary subsets: insulin resistance and vitamin D deficiency.

Signs of insulin resistance typically include high blood pressure, high triglycerides, high cholesterol, obesity, and other variables connected with it.

In the United States, NHANES data published in 2016 reveal 87.8 percent of Americans are metabolically unhealthy, based on five parameters. That data is more than four years old now, so the figure is likely greater than 90 percent of the population today.

According to a January 2019 update by the U.S. Centers for Disease Control and Prevention, more than 122 million American adults have diabetes or prediabetes—conditions which have been shown to increase your chances of contracting and even dying from COVID-19.

Metabolic Syndrome Triples COVID-19 Fatality Risk

While abdominal obesity and insulin resistance are hallmark characteristics of someone with metabolic syndrome, they don’t count as metabolic syndrome on their own. That distinction becomes more important when it comes to COVID-19, Malhotra notes.

“The data from COVID-19 shows the highest risks of death and hospitalization are in people with metabolic syndrome, not obesity. Obesity probably doubles your risk of death, but with metabolic syndrome, it’s around a 3.5 times increased risk of death—more than threefold—and about five times the risk of hospitalization if you get COVID-19.

“So that is the major problem. And the reason why that’s important is it also affects many, many people. This is why BMI [body mass index], to be honest, I think should be thrown out; I mean, it’s useless, it’s outdated.”

“We should be looking at metabolic health, because up to 40 percent of people with a so-called normal BMI, who may be told they’ve got a healthy weight, actually are metabolically unhealthy. That’s a huge proportion of people, and there are disparities depending on which ethnicity you’re from.”

The problem with BMI is it is based solely on weight and height, without factoring in body fat percentage, muscle mass, or ethnicity, says Malhotra.

“It misses a huge group of people who are probably vulnerable and could institute lifestyle changes to help themselves if they were advised to do so. But a lot of them aren’t being advised because they’re being told they’ve got a healthy weight.”

“If everybody knew their metabolic health markers and were then given advice to do things about it, then, as I point out in the book, within a few weeks you’d probably notice significant changes. Of course, it’s going to vary from person to person.”

Another crucial factor to immune function is vitamin D. Malhotra says this crucial link is overlooked. Vitamin D deficiency is a well-known and widespread problem in the United States and United Kingdom.

“Most cell receptors in your body have vitamin D receptors, and it is involved in enhancing both innate and adaptive immunity,” says Malhotra.

The bottom line is you need to have the five metabolic parameters listed above within the normal ranges, and you need an optimal blood level of vitamin D, which is now thought to be between 40 ng/mL and 60 ng/mL.

“There was a study in Indonesia that showed that in people hospitalized with COVID-19—those who had severe vitamin D deficiency versus those that had normal ranges of vitamin D in their blood—there was a tenfold difference in death rates, which is extraordinary. So, [vitamin D] certainly has a very important role to play,” Malhotra says.

“The ideal scenario is to get vitamin D from sunlight because it actually stays in your bloodstream longer. But, certainly, at least through the winter months, you should be taking a supplement. And I think the good thing about that is it’s cheap.”

“I suspect getting good health actually is going to come from just eating real food, and being out in nature, and doing more exercise, and reducing our stress, and social connection; all of those things, I think, are the key to longevity and good quality of life.”

How to Improve Your Metabolic Health

So, just how do you improve those five metabolic parameters? Malhotra addresses this in his book, of course. In summary, to optimize your metabolic health and reverse metabolic syndrome, you’ll want to mind your diet, activity, sleep, and stress.


Limit or eliminate foods that promote insulin resistance. Topping this list are processed foods high in industrial seed oils, added sugars, and refined carbohydrates (i.e., bread, pasta, and white rice).

“Sugar is probably one of the major dietary culprits,” Malhotra says. “It certainly also, beyond its calorie issue, seems to have independent effects and adverse effects on metabolic health.

Malhotra says eliminating sugar is one of the first things he raises with people. Sugar cravings can be difficult for some people, but Malhotra says they pass.

“Most people you can break those addictions usually within three to six weeks.”

Another major dietary issue is the widespread use of industrially processed seed oils such as canola, corn, and soy oil—most of which are also genetically engineered. These appear to be a central factor in most—if not all—chronic diseases of the modern world.

Evidence suggests they may be an even greater health threat than added sugar. Malhotra has also addressed this issue in his book, “The Pioppi Diet,”23 published in 2017. Aside from more direct harms, one of the ways in which these oils undermine your health is by skewing your omega-3 to omega-6 ratio, as they’re excessively high in omega-6 linoleic acid.

When used in cooking, they also produce toxic, carcinogenic aldehydes. In lieu of seed oils, use healthy saturated fats such as coconut oil, grassfed butter, organic ghee, or lard.


Be more physically active. This too can ameliorate and reduce metabolic disease risk markers. Just be mindful not to go overboard, as excessive exercise will actually lower your immune function and put you at increased risk of respiratory infections.


Be sure to optimize your sleep. It is crucial to your body’s renewal cycle, and a lack of sleep is linked to increased risk of many diseases.


Manage your stress. Stress spurs the release of the stress hormone cortisol. This reaction is helpful in short-term situations when you need to flee a threat or focus your attention on immediate threats to your survival.

But this reaction brings a host of problems to modern life. In the end, the ongoing influence of cortisol leaves the body depleted and vulnerable to a host of disease.


As we face the risk of COVID-19, it is critical to be aware that our lifestyle will have a major impact on our risk of a severe infection or possible death from the virus. Taking the steps above will help lower that risk. Tending to these aspects of lifestyle will also ensure overall health.

“Combining all those together—that synergy of the diet and all the other lifestyle factors—has profound and rapid effects on health. So that’s where we need to change the narrative,” says Malhotra.

“One of the bits of advice to start with is what you should cut out ultra-processed food and low-quality carbs. At least go cold turkey for a few weeks. You may reintroduce them or have them as occasional treats, but this should not be making up the bulk of your calorie consumption.”

“That is really where we need to start.”

To learn more, be sure to pick up a copy of Malhotra’s book “The 21-Day Immunity Plan.” It’s an easy read that emphasizes and summarizes the core lifestyle basics you need to understand and apply to improve your metabolic health, which in turn will reduce your risk of complications should you come down with symptomatic COVID-19 illness. Social media info for Dr. Malhotra can be found on his site at

Dr. Joseph Mercola is the founder of An osteopathic physician, best-selling author, and recipient of multiple awards in the field of natural health, his primary vision is to change the modern health paradigm by providing people with a valuable resource to help them take control of their health. This article was originally published on