The benefits of fasting are many and various. Fasting supports good health by promoting a healthy body weight, encouraging normal cognitive function, and even facilitating detoxification. Now, research has also shown that fasting may help reset the immune system.

How Does Fasting Reset the Immune System?

Like every other system in the body, the immune system is subject to wear and tear. Aging, aggressive medical therapies, oxidative stress, environmental toxins, and the like can all accelerate the degradation of immune cells.[1, 2, 3] When immune cells are weak and frail, they’re not as effective as they should be in protecting your health. This is where fasting can help.

When you fast, your body looks for nourishment everywhere it can. It goes after stored fat, but it also recycles malfunctioning or inactive cells, like those old, worn out immune system cells. This cell recycling process, known as autophagy, makes room for your body to create fresh, new immune cells. It’s similar to spring cleaning, in that you declutter your body and end up with a rejuvenated immune system. Many people, especially those whose immune system is compromised, make a concerted effort to fast for a few days once or twice every six months to reset and reboot their immune system with fresh, strong cells.

How to Perform a 3-Day Fast

Forty-eight hours appears to be the minimum duration to see benefits to the immune system, but it may take a bit longer for the desired effect. A three day fast is a long enough duration to see some of the benefits, but short enough that most people wont need professional supervision.

If you’ve never performed a fast before, start small. Going a full three days without eating can be emotionally and mentally stressful if you’re not prepared for the side effects. Start with intermittent fasting, a pattern of eating that involves alternating cycles of fasting and eating. Try extending how long you go between meals. Slowly increase the amount of time between meals until you can go most of the day without eating food.

If you tolerate this well and aren’t under the care of a health care professional, you can try alternate day fasting. When you feel ready, you can embark on an extended water fast to boost the immune system even further.