What are the stages of fasting?

Dr. Berg Nutritionals does not encourage prolonged fasting. We are not healthcare professionals equipped with the tests and facilities to perform the necessary monitoring during a prolonged fast, nor do we have an individual's medical health records. Dr. Berg Advisors provides this document based on Dr. Berg's education for informational purposes only to those already on a prolonged fast or independently choosing to do one.

Always consult with your healthcare provider before starting a prolonged fast. If you're considering prolonged fasting, discussing the benefits and risks with your healthcare provider is essential.

The six stages of fasting:

Stage 1: 8-14 hours

• Stable blood sugar levels

• Using up stored sugar and sugar in the blood

• At 10 hours—the muscles use about 50% glucose and 50% fat (you’re starting to transition to fat-burning)

Stage 2: 14-24 hours

• Starting to get into ketosis

• Fewer cravings

• More energy

• Improved mood

• Improved cognitive function

Stage 3: 24-36 hours

• Full ketosis and fat burning

• The liver is making ketones

• Decreased appetite

• Decreased ghrelin

• Increased BDNF (new brain cells)

Stage 4: 36-48 hours

• Autophagy

• Kill cancer cells

• Decreased oxidative stress

• Decreased misfolded proteins

• Increased memory

Stage 5: 48-60 hours

• Insulin sensitivity super boost

• More autophagy

• Less inflammation

• Atrophy healing

• Protein sparing

Stage 6: 60-72 hours

• Immune system regeneration

• Spike in immune stem cells

• A 2014 study demonstrated that a 72 hour fast led to a complete rejuvenation of the immune system, and people on chemotherapy had less damage