Fasting and Immune Function

Research from USC demonstrated that fasting can dramatically stimulate immune system regeneration. Chronic intermittent fasting may reduce COVID-19 vulnerability by improving body composition and metabolic health. No randomized controlled trials of fasting for COVID-19 existed at the time of recording. Fasting upregulates autophagy, stimulates mitochondrial biogenesis, and exerts a hormetic effect that strengthens the immune system over time. Approximately 75 to 80 percent of the immune system resides in the gut. The gut microbiome has its own circadian rhythm with different bacterial colony populations peaking at different times of day, and constant food intake can interfere with this rhythm. Elevated BMI, type 2 diabetes, and hypertension are the dominant risk factors for severe COVID-19, not pre-existing pulmonary conditions. Fasting appears genuinely beneficial and potentially lifesaving during serious bacterial infections. Eating during active viral illness is preferable because the body appears to benefit from fuel when fighting a virus.