Menu Close

What Really Happens to Your Body When You Intermittent Fast? PART 1

Bridgette Ruge Barlow, MA, RHC, CPT

Intermittent fasting has become a hot topic in the health and fitness world in recent years. Is it all hype or is there something to it? Turns out the science is showing incredible benefits of fasting that go way beyond weight loss. We are talking about restoring optimal metabolic function, normalizing blood levels of lipids and blood sugars, anti-aging, increasing muscle mass, and healing chronic disease conditions. Intermittent fasting is something that anyone can do and reap benefit – whether you stick to shorter fasts or attempt longer ones.  As your health coach at SaJune, I will help you determine which fasting protocols are appropriate for you based on your health history, how you are feeling, and your current hormone levels. I do not recommend attempting long fasts (18+ hours) before having a consultation with one of our providers to assess your hormone levels. While mostly anyone can fast, knowing this information can help you structure the best fasting plan for you while feeling your optimal best.

In this article we will look at the benefits of short-term fasting – up to 24 hours. In Part 2, I will go into the benefits of longer fast-up to 48 and 72 hours.

So let’s examine what happens in the body at various stages of fasting:

12 hrs – After about 12 hours of fasting, we see a spike in human growth hormone, a natural hormone with great benefits including slowing the aging process, healing, stimulating muscle growth, regulating sugar and fat metabolism, and improving heart function.  This increase in HGH will continue as the fast continues if you go for longer periods. Normally there is a stimulation in HGH with exercise so fasting is a bit of a hack to reap some of the benefits of exercise, even if you aren’t exercising or are unable to exercise.  However, adding exercise to the very end of a fasting window is a great way to increase the benefits of your fast and burn more fat if your goal is weight loss. It’s best to keep this workout shorter in length and light, depending on how to feel while fasting. With practice at intermittent fasting, this will feel quite easy to do and you should not feel unwell or hungry while exercising during a short fast. Work with a coach to determine the best way to get started with intermittent fasting to best fit your lifestyle and health goals. Also, it is recommended to work with a coach when beginning fasting if you have diabetes and/or uncontrolled blood sugars.

Pro Tip: 12 hours is a great way to start intermittent fasting if you’ve never done it before. Once you’re accustomed to 12 hours, a daily practice of 14-18 hours will greatly enhance the benefits.

18 hrs – After about 18 hours of intermittent fasting the body begins the process of autophagy – or the cleaning out of damaged cells to regenerate new, healthy cells.  During this stage, the body cleans out fungus, mold and yeast and make hydrogen peroxide to kill microbes. Autophagy is an importance process, as an accumulation of old, damaged cells is often what leads to Alzheimer’s Disease or cancers. During this stage of fasting Amyloid plaques are decreased, leading to better brain function. Most people report that they are thinking more clearly at this stage of fasting. This makes sense considering that when they body is in a fasted state, the human brain increases all senses and clarity in order to find its next meal – a survival mechanism. Autophagy is not achieved through calorie restriction or dieting, and even a small amount of glucose will break this process so intermittent fasting is the best way to achieve this process. At around 18 hours is also where the body will see a reduction in Advanced Glycation End Products (AGEs) which increase with age and are associated with the complications of diabetes, kidney disease, metabolic disorders, and degenerative diseases.

Pro Tip: 18 hour fasting can be done daily. Even a regular practice of 14-16 hours can produce incredible health benefits and optimize weight. Work up to this if you’ve never fasted before. – 

24 hrs – After about 24 hours liver glycogen (stored sugars) deplete and the body enters ketosis. At this stage, the liver sees great benefit, especially for those with fatty liver, since the body will use the fat in the liver and convert it to ketones for the body to use for fuel and energy. Ketones also act as an appetite suppressant, so hunger dramatically deceases around 24 hours. Around 24 hours, inflammation decreases so those with autoimmune conditions and pain see a decrease in symptoms. This is also where the gut does major healing and those with severe gut conditions, such as SIBO, are able to heal. Over time of practicing fasting, Brain Derived Neurotropic Factor (BDNF) increases. The protein, BDNF, influences brain function and the peripheral nervous system. It prevents death of existing brain cells and encourages the growth of new neurons and synapses.  Low BDNF has been linked to Alzheimer’s, accelerated aging, poor neural development, obesity, depression, and schizophrenia.  

Pro Tip: 24 hour fasting can be done once per week but even once per month will show benefit. Work up to this length of fasting and consider working with a coach.

Other fasting tips:

  • During fasting, always drink plenty of water with added minerals. For minerals you can use a high mineral pink salt, such a Premier Research Labs pink salt or Premier Research Labs “ph minerals” drops. You may also add lemon juice.
  • Coffee or tea is fine during a fast if you’re not adding any sugar or sugary creamers. You can use organic stevia or monk fruit and a splash of organic half and half or unsweetened dairy free coffee creamer or milk of choice.
  • You can exercise during a fast but keep it to the end of your fasting window to avoid feeling very hungry while trying to finish out your fast.

References to studies:


Let Us Help You!

Interested in doing intermittent fasting but need some guidance and advice? Looking for someone to hold you accountable to your goals and give you more tips along the way?

Bridgette Ruge Barlow is SaJune Institute’s Certified Regenerative Health Coach. She’s been working with Dr. Pati for 5 years and helping countless patients achieve optimal health!

Schedule your consult now to get started  https://sajune.com/book-now/