Is It Time for a Lockdown on Sugar? : Clinical Journal of Sport Medicine

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Is It Time for a Lockdown on Sugar?

Cucuzzella, Mark MD, FAAFP*; Teicholz, Nina MPhil

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Clinical Journal of Sport Medicine 32(3):p 233-235, May 2022. | DOI: 10.1097/JSM.0000000000000915
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As we reopen society and search for medicines and vaccines that could improve coronavirus outcomes, we should not miss the opportunity to talk about the conditions that have increased our vulnerability to this pandemic in the first place: America's poor state of health. Some 60% of us has one or more diet-related, chronic disease and the cost of this is a staggering contribution to the 3.5 trillion dollar annual US health care expenditure. These diseases have accompanied a large majority of severe cases in the United States, according to the Centers for Disease Control and Prevention (CDC) with the 2 most common underlying health conditions being cardiovascular disease (32%) and diabetes (30%).1 Hospitalizations were 6 times higher and deaths 12 times higher among those with reported underlying conditions compared with those with none reported.1 In a large study in the New York City of 5700 patients hospitalized with COVID-19%, 57%, 42%, and 34% had hypertension, obesity, and diabetes, respectively.2

Obesity is clearly emerging as a dominant factor greatly increasing the risk of hospitalization and death.3–6 In one of the most recent studies on comorbidities to date, conducted in France, only 1 in every 10 people who ended up in intensive care with Covid-19 were in a range of healthy weight. Researchers led by Francois Pattou, the head of Lille University Hospital's general and endocrine surgery department in France, presented data at a conference showing that about half of the 124 intensive-care patients with Covid-19 in a sample they studied were obese, and most of the remaining ones were overweight.7 Thus, to build resilience to this and future viruses, we need to talk about better nutrition.

In the United Kingdom, the National Health Service reports that over a quarter of fatalities from Covid are accompanied by diabetes.8 Prime Minister Boris Johnson became convinced that his own obesity contributed to his hospital stay, prompting him to declare, on launching a probe into the link between obesity and worsened Covid outcomes, “I have changed my mind on this [obesity]. We need to be much more interventionist.”


Early on, experts attributed the high mortality rates from the virus to air pollution, smoking, and advanced age; yet over the past months, the significant risk of metabolic illness has emerged. This is even more pronounced in our minority populations. Minorities who have higher rates of comorbidities and diet-related illness are being affected at higher rates.9–11

Indeed, a recent report found that per-capita death rates from Covid-19 have increased dramatically over the summer for Black and Brown Americans. Although fatalities also increased for White Americans, yet the impact on this group has been notably less severe. The latest figures record that in the 2 weeks from 4 to 18 August the death rate of African Americans shot up from 80 to 88 per 100 000 population—an increase of 8 per 100 000. By contrast, the White population suffered half that increase, from 36 to 40 per 100 000, an increase of 4 per 100 000. For Latino Americans, the increase was even more stark, rising from 46 to 54 per 100 000—an increase of 9 per 100 000 when rounded.9 The most recent US CDC data reveal almost 5 times the hospitalization rates for Blacks and Latinos versus Whites.12


Almost all of these comorbidities—hypertension, diabetes, coronary artery disease, and obesity—have a common root cause, called insulin resistance,13 which is diagnosed when a person has a spectrum of symptoms, including abdominal obesity, low High Density Lipoprotein-cholesterol, high triglycerides, high blood pressure, and high blood sugars. According to one recent estimate based on government data, no less than 88% of Americans may currently have insulin resistance. This means that only 12% of our population is metabolically well. Given that chronic diseases are strongly implicated in poor outcomes for coronavirus, we need to take insulin resistance far more seriously.14


Insulin resistance has been called a “metabolic storm” in the body, where normal function breaks down. The principal malfunction is related to the body's inability to process sugars in the blood. Whereas a healthy body reacts to sugar consumption by stimulating the pancreas to secrete insulin, which then shunts the sugar off to be stored in the liver, muscles, or fat tissues, at some point, this insulin mechanism is overwhelmed. An overabundance of sugar in the blood stream, throughout the day and after many months, erodes the body's ability to respond to insulin, a state known as insulin resistance. Levels of circulating insulin rise. This ultimately leads to any number of conditions, from type 2 diabetes and obesity to nonalcoholic fatty liver disease and heart disease.

Figure 1.:
WHO message on Covid and sugar reduction.

The primary driver of this excess sugar in the blood stream is the food we eat. The reality is that not only do simple sugars such as candy convert to blood sugar, but so do more “complex” carbohydrates, such as bread, pasta, crackers, and even sweet fruits. These all become sugar—glucose—as soon as they are digested. Thus, to avoid high blood sugar, the logical solution is to cut down on eating them. Easier said than done, of course, but there are now some 100 clinical trials showing, altogether, that carbohydrate restriction is safe and effective for sustainably reversing a diagnosis of type 2 diabetes, bringing down blood pressure, improving most cardiovascular risk factors, and helping people to lose weight.


Based on the emerging data, obesity and other chronic diseases might contribute to more acute Covid outcomes through the following possible mechanisms.

The ACE-2 Receptor

A virus works by gaining access to the cells of its host and hijacking a receptor on that cell. In the case of Covid, access is obtained by the ACE-2 receptor, which explains why the virus gains access so readily through the lungs and small intestine—because these tissues have ample ACE-2 receptors. There is some logic to the idea that metabolically ill people, because they tend to have higher ACE-2 expression, are therefore more vulnerable to the virus.

Endocrine and Metabolic Link

A recent paper in Nature15 discusses how the Coronavirus might exacerbate, or even cause, diabetes by seriously damaging the pancreas. Specifically, it attacks pancreatic islets, where insulin is formed. People with diabetes are at a heightened risk for the virus, because these impaired pancreatic cells, combined with Covid-induced pneumonia, may in fact form a vicious circle, amplifying the negative effects of the virus.

More recently, we have been witnessing unusual cases of clotting and strokes. A 2006 paper in Diabetes suggests that people who are more insulin resistant are less likely to have clots dissolve and are “especially susceptible to thrombotic events by a concurrent insulin-driven impairment of fibrinolysis and a glucose-driven activation of coagulation.”16

Immune Dysregulation

People with insulin resistance are likely also vulnerable to the virus because of their weakened immune system.17The immune system exists in 2 parts: an innate, first responder and a more delayed, adaptive second responder which provides additional immunity. Both of these arms combine to reflect one's overall health, and both of these immune system arms are negatively impacted by obesity and metabolic syndrome. In 2017, biologist Catherine Anderson explored this topic,18 and in 2019, researchers added to the discourse in Nature,19 stating:

“…during respiratory viral infections, insulin-resistant participants respond differently than insulin-sensitive participants. Third, global coassociation analyses among the thousands of profiled molecules reveal specific host–microbe interactions that differ between insulin-resistant and insulin-sensitive individuals.” (Emphases added)

Importantly the article explains how the more delayed and robust cytokine release in insulin-resistant patients may contribute to the “cytokine storm.” Moreover, visceral adipose tissue itself contributes to the cytokine storm.20,21

High Blood Sugar

Persistently high blood sugar clearly hinders immune responses, according to a 1972 paper,22 which states, “hyperglycemia [high blood sugar] negatively affects white blood cell defense against infection. High glucose impairs these cells in the innate immune response to invading organisms.”

More recently, high blood sugar was found, in an analysis of more than 7000 Chinese Covid patients to be the single-most important determinant of outcomes for hospitalized patients.23 Researchers found that mainly because of high-blood sugar, subjects with type 2 diabetes required more medical interventions and had a significantly higher mortality (7.8% vs 2.7%) and multiple organ injury compared with nondiabetic individuals.


Recently, the World Health Organization launched a Stay Healthy At Home Campaign, urging adults to limit their sugar consumption to less than 6 teaspoons a day—the amount of sugar in one small carton of chocolate milk served to school children.

The reality is that we are partially responsible for our fragility to the coronavirus. Now, we are hoping for a vaccine and medications to pull us out of this pandemic. But the current crisis reveals how truly vulnerable we are. We have often blamed the victim for having obesity or other diet-related diseases, but these illnesses now affect up to 80% of the world's population.24 Our current Covid-19 approach has focused on hiding from the virus and now hoping immunization will set us free. We believe the best idea going forward instead is to strengthen our resistance to Covid and future viruses, with a healthy immune system—which means a healthy lifestyle.

Reducing sugar and refined carbohydrates, which together fuel insulin resistance, is an ideal first step. Eating to keep blood sugar low and stable will clearly reduce risk. Anyone can purchase a continuous glucose monitor to know exactly how foods are affecting blood sugar levels. Junk food is the obvious enemy, even if it can be every quarantiner's best friend. Yet even these comforting foods can be resisted when replaced by whole, natural foods including filling fats and proteins. It is also critical to focus the diet on foods that are nutrient dense: meats, eggs, seafood, dairy, vegetables, and low-sugar fruits.

Many people who aim to achieve good health aim to do so through natural means, such as better nutrition and other lifestyle changes. So instead of managing their conditions with pills, they seek to reverse chronic disease through more natural approaches. This strategy, such as a vaccine, should provide protection now and for many years to come, and that is essential, since Covid-19 will not be like a blizzard (hitting hard and quickly passing over) but rather like a long hard winter. We all can get healthier, and this applies especially to those with metabolic illness.

Each comorbidity you have decreases your physiological reserve. We should be doing a better job in maintaining our health for times when we are under stress.

We hope to see a new world where people have the tools to recover their good health and become stronger to fight pandemics such as this one. We are probably in mile 4 now of the 26 mile Covid marathon, and even as the coronavirus abates, the ongoing obesity, diabetes, and metabolic disease pandemics will continue to take their toll on our society. It is time to take back our health, our own resilience—and that of our nation.


1. Stokes EK, Zambrano LD, Anderson KN, et al. Coronavirus disease 2019 case surveillance—United States, January 22–May 30, 2020. MMWR Morb Mortal Wkly Rep. 2020;69:759–765.
2. Richardson S, Hirsch JS, Narasimhan M, et al. Presenting characteristics, comorbidities, and outcomes among 5700 patients hospitalized with COVID-19 in the New York City area. JAMA. 2020.
3. Available at: Accessed October 1, 2020.
4. Popkin BM, Du S, Green WD, et al. Individuals with obesity and COVID‐19: a global perspective on the epidemiology and biological relationships. Obes Rev. 2020;1–17. Available at:
5. Tartof SY, Qian L, Hong V, et al. Obesity and mortality among patients diagnosed with COVID-19: results from an integrated health care organization. Ann Intern Med. 2020;173:773–781.
6. Rizzo S, Chawla D, Zalocusky K, et al. Descriptive epidemiology of 16,780 hospitalized COVID-19 patients in the United States. MedRxiv. 2020.
7. Available at: Accessed October 1, 2020.
8. NHS Database. Available at: Accessed October 1, 2020.
9. Available at: Accessed October 1, 2020.
10. Williamson EJ, Walker AJ, Bhaskaran K, et al. Factors associated with COVID-19-related death using OpenSAFELY. Nature. 2020;584:430–436.
11. Cucuzzella MT. The differential impact of covid-19 on neighbourhoods of colour. Br J Gen Pract Life. 2020. Available at: Accessed May 20, 2020.
12. Available at: Accessed October 1, 2020.
13. Cucuzzella MT, et al. A low-carbohydrate survey: evidence for sustainable metabolic syndrome reversal. J Insul Resist. 2017;2:a30.
14. Araújo J, Cai J, Stevens J. Prevalence of optimal metabolic health in American adults: national health and nutrition examination survey 2009–2016. Metab Syndr Relat Disord. 2019;17:46–52.
15. Bornstein SR, Dalan R, Hopkins D, et al. Endocrine and metabolic link to coronavirus infection. Nat Rev Endocrinol. 2020;16:297–298.
16. Stegenga ME, van der Crabben SN, Levi M, et al. Hyperglycemia stimulates coagulation, whereas hyperinsulinemia impairs fibrinolysis in healthy humans. Diabetes. 2006;55:1807–1812.
17. Smith M, Honce R, Schultz-Cherry S. Metabolic syndrome and viral pathogenesis: lessons from influenza and coronaviruses. J Virol. 2020;94:e00665–20.
18. Andersen CJ, Murphy KE, Fernandez ML. Impact of obesity and metabolic syndrome on immunity. Adv Nutr. 2016;7:66–75.
19. Zhou W, Sailani MR, Contrepois K, et al. Longitudinal multi-omics of host–microbe dynamics in prediabetes. Nature. 2019;569:663–671.
20. Petersen A, Bressem K, Albrecht J, et al. The role of visceral adiposity in the severity of COVID-19: highlights from a unicenter cross-sectional pilot study in Germany. Metab Clin Exp. 2020;110:154317.
21. Huizinga GP, Singer BH, Singer K. The collision of meta-inflammation and SARS-CoV-2 pandemic infection, Endocrinology. 2020;161:bqaa154.
22. Bagdade JD, Nielson KL, Bulger RJ. Reversible abnormalities in phagocytic function in poorly controlled diabetic patients. Am J Med Sci. 1972;263:451–456.
23. Zhu L, She ZG, Cheng X, et al. Association of blood glucose Control and outcomes in patients with COVID-19 and pre-existing Type 2 diabetes. Cell Metab. 2020;31:1068–1077.
24. Maffetone PB, Laursen PB. The prevalence of overfat adults and children in the US. Front Public Health. 2017;5:290.
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