Coronavirus Chronicles: How Does Inflammation Come Into the Picture?

There is more to be said about the conjunction of obesity, inflammation, and the disease. For instance, why does COVID-19 prefer to afflict obese people, and why does it give them a particularly hard time, compared with people whose weight is in the normal range?

Inflammation is basically defense mode. Cells contain mitochondria, which convert fatty acids to energy, and when there are too many fatty acids to handle, the mitochondria are stressed and eventually damaged. An accumulation of damaged mitochondria kicks off the immune response.

In adipose tissue, or fat, most of the immune cells are macrophages. Here is one capsule description:

Fatty tissue in the body is comprised of adipose cells (adipocytes), which increase in volume but not in number, and primarily expand based on poor diet choices and a sedentary lifestyle. Adipocytes also contain self-defensive macrophages which have shown to produce cytokines, or a general name to describe various pro-inflammatory substances in the body.

Macrophages are the disposal system to get rid of bacteria and other invaders, but the process causes fat cells to release cytokines, and they trigger inflammation. Short-term inflammation means some good cleanup work is being done, but long-term it is not beneficial. Unfortunately, obesity appears to guarantee a pretty much perpetual state of inflammation. That sets off insulin resistance and diabetes.

It has been said that aging and obesity both involve chronic inflammation, which triggers the symptoms of disease, and causes nearly all chronic health issues. Dr. David M. Marquis uses the word “smoldering,” inviting comparison with an ember that devours the stuffing of a sofa for a while before finally becoming a legit fire. He wrote,

1 in 12 women and 1 in 24 men are dealing with full blown autoimmune mediated inflammation. The number of undiagnosed people is going to be much higher.

So a lot of people are walking around full of cytokines that are poised to do any number of destructive things, like delay post-surgical healing. Let’s get back to the virus causing this pandemic.

The medical profession wants to know two things right now: how to improve the prognosis of patients who are hospitalized, and how to prevent the spread of the disease. August establishments like the World Obesity Federation and the Centers for Disease Control and Prevention are discovering that obesity and its complications are bad news when it comes to COVID-19.

Obesity causes hyperglycemia by way of insulin resistance, and the virus appears to also cause hyperglycemia by an as-yet-unknown mechanism. Adipose tissue, aka fat, causes low-grade inflammation that is a constant background in the bodies of obese people. Then the virus comes along and stirs up more inflammation, which raises the levels of cytokines.

(To be continued…)

Your responses and feedback are welcome!

Source: “Being overweight causes hazardous inflammations,” ScienceDaily,com, 08/25/14
Source: “Fat’s Role in Causing Inflammation,”, 11/07/12
Source: “How Inflammation Affects Every Aspect of Your Health,”, 12/08/15
Source: “SARS-CoV-2 infection and obesity: Common inflammatory and metabolic aspects,”, 04/29/20
Image by Muenocchio via Flickr

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About Dr. Robert A. Pretlow

Dr. Robert A. Pretlow is a pediatrician and childhood obesity specialist. He has been researching and spreading awareness on the childhood obesity epidemic in the US for more than a decade.
You can contact Dr. Pretlow at:


Dr. Pretlow’s invited presentation at the American Society of Animal Science 2020 Conference
What’s Causing Obesity in Companion Animals and What Can We Do About It

Dr. Pretlow’s invited presentation at the World Obesity Federation 2019 Conference:
Food/Eating Addiction and the Displacement Mechanism

Dr. Pretlow’s Multi-Center Clinical Trial Kick-off Speech 2018:
Obesity: Tackling the Root Cause

Dr. Pretlow’s 2017 Workshop on
Treatment of Obesity Using the Addiction Model

Dr. Pretlow’s invited presentation for
TEC and UNC 2016

Dr. Pretlow’s invited presentation at the 2015 Obesity Summit in London, UK.

Dr. Pretlow’s invited keynote at the 2014 European Childhood Obesity Group Congress in Salzburg, Austria.

Dr. Pretlow’s presentation at the 2013 European Congress on Obesity in Liverpool, UK.

Dr. Pretlow’s presentation at the 2011 International Conference on Childhood Obesity in Lisbon, Portugal.

Dr. Pretlow’s presentation at the 2010 Uniting Against Childhood Obesity Conference in Houston, TX.

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