A review of 4,103 patients found that obesity and its resultant inflammation, heart disease and diabetes are the most common conditions found in patients requiring hospitalization with COVID-19 (Physician’s Weekly, pre-print, April 14, 2020). Another study of 3,615 patients found that in patients under 60 years of age, being obese more than doubled the chance of needing to be hospitalized (Clinical Infectious Diseases, April 9, 2020). Other studies show that obesity (body mass index or BMI greater than 30) is a major risk factor for dying from COVID-19 (Lancet, April 1, 2020), and the more you weigh, the more likely you are to need to be put on a ventilator which markedly increases your chance of dying (Obesity, April 9, 2020). This should scare you into action because more than 40 percent of North Americans are obese.

The 2009 Influenza A virus pandemic was caused by a virus very similar to the one that caused the 1918 Flu pandemic, and obesity was associated with increased risk of severe disease, hospitalization and death (PLoS ONE, 2010; 5:e9694). During the 1957-1960 Asian flu and the 1968 Hong Kong flu, both obesity and diabetes were associated with a marked increase in prolonged illness and death (Prev Med, 2013;56(2):118-123), even in those who were apparently healthy before they got the flu (Influenza Other Respiratory Viruses, 2019;13:3-9).

How Does Obesity Increase Risk for Death from COVID-19?
Obese people suffer increased risk for complications from infections because obesity leads to an overactive immune system called inflammation (Adv Nutr. 2016;7:66-77) that interferes with their body’s ability to kill invading germs (Epidemiology, July 2015;26(4):580-589). An article in Acta Diabetologica (April 5, 2020) explains how obesity causes inflammation:
• A major cause of obesity is inability to respond to the hormone, leptin (Am J Physiol Regul Integr Comp Physiol, 2009 Mar; 296(3):R493–R500), just as type II diabetes is caused by insulin insensitivity.
• Leptin is a hormone made by fat, intestinal cells and red blood cells.
• Leptin inhibits hunger by telling your brain that you are full so that you stop eating, don’t take in too many calories, and therefore do not fill up fat cells with excess fat.
• Obese people have very high blood levels of leptin because they do not respond to leptin (leptin insensitivity), and keep on eating long after they are full.
• High levels of leptin turn on your immune system to cause inflammation, and reduce levels of adiponectin, a hormone that reduces inflammation.
• Obesity-related chronic inflammation prevents your immune system from producing cells and cytokines to kill invading viruses (Environ Toxicol Pharmacol, 2015;40(3):924-930).
• People who have high levels of leptin and low levels of adiponectin suffer from inflammation to cause diabetes (insulin insensitivity), infections (high white blood cell counts), and heart, liver and kidney damage (Nat Rev Immunol, 2011;11(2):85-97).

Lack of Exercise
Lack of exercise causes the same harms as obesity. Each of the changes listed above are also promoted by lack of exercise (Nature Medicine, 2019;25:1761-1771). Lack of exercise increases risk for insulin resistance (Acta Physiol, 2019;226:1-16), and prevents your body from responding to infections and mounting a full attack on invading viruses (Cell Physiol Biochem, 2015;37:735-746).

My Recommendations
The current COVID-19 pandemic is probably keeping you at home and away from group activities, so you are stuck with lots of food and limited opportunities for exercise. Eating more food and exercising less sets you up to gaining extra fat weight.
• Try to exercise at home or outdoors as long as you are not near other people.
• Avoid bringing the foods that are most likely to make you fat into your home, particularly added sugars and refined carbohydrates (breads, crackers, cookies, and other foods made from flour).
• Drink water or other fluids that contain no calories.