7 Benefits of Fasting (That Have Nothing To Do With Weight Loss)


When I say the words “intermittent fasting” do you think about hunger, scarcity, and weight loss? If you do, you’re not alone. And I get it! Technically, fasting means NOT eating, so it makes sense that it’s often associated with restriction and diet culture. 

But here’s what I say in my new book Intuitive Fasting that I also want you to know here today: Fasting is about way more than weight loss. In fact, if you think about fasting the way I do, weight loss isn’t even center stage when it comes to fasting’s benefits. In fact, it really doesn’t have to be on stage at all.   

So if not weight loss, then what are the benefits of intermittent fasting (IF)? Fasting causes fundamental shifts in your body’s physiology —  such as improvements in glucose regulation, blood pressure, and heart rate — that are completely separate from its effect on your weight. Human and animal studies have shown that the benefits of fasting are not simply the result of fasting-induced weight loss. Instead, they explain that intermittent fasting awakens powerful healing mechanisms that were lying dormant inside of you. Fasting enhances health and leads to weight loss in ways that are unrelated to a calorie deficit. Instead, fasting triggers shifts in metabolic and hormonal pathways that bring balance back to the body and allow it to maintain a healthy weight more easily, naturally. 

So, let’s talk about these shifts and what they can do for your health — leaving weight loss out of the conversation entirely.


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1. Better digestion 

No one likes to feel bloated or suffer from indigestion, gas, or diarrhea or constipation. Unfortunately, so many of us do deal with digestive issues and even conditions like irritable bowel syndrome or inflammatory bowel disease. This can leave many people eliminating major food groups and on an endless cycle of eliminating foods that may or may not trigger their digestive issues. This can be incredibly frustrating and start to affect a person’s relationship with food. That’s why I often recommend a fasting protocol for digestive issues. Studies have shown  that intermittent fasting lowers gut inflammation to help improve inflammatory gut disorders such as Crohn’s disease, ulcerative colitis, and IBS. Fasting for 12 hours a day for 6 months can also significantly improve markers of inflammation in the gut, like c-reactive protein and serum interleukin-6. (1) 

2. Better brain health 

This is one of the most exciting emerging benefits of fasting. Strong preclinical evidence is showing that fasting can prevent and slow down the progression of conditions Alzheimer’s disease and Parkinson’s disease. Pretty incredible, isn’t it? It does this by increasing the ability for brain cells to resist stress and stimulating autophagy, boosting mitochondrial function, antioxidant defenses, and DNA repair, according to a study published in the New England Journal of Medicine. (2) Some researchers think that because ketones are a more efficient energy source than glucose, they may protect against age-related decline in the central nervous system that might cause dementia and other brain-related illnesses; fasting can also increase levels of factors the brain that support neuroplasticity, which is the brain's ability to reorganize itself and form new neural connections throughout your lifetime. 

3. Better blood sugar control 

The CDC estimates that about half of the United States is either prediabetic or diabetic. That’s not a typo — 50 percent of Americans have a major blood sugar problem. Even more, 1 in 4 of these people don’t know they have diabetes, which means they’re doing unknown damage to their body every single day!  About 90 to 95 percent of diabetes cases are type 2 adult-onset diabetes, which means that almost all of them are lifestyle-related. When patients come in with blood sugar problems, I like to recommend IF due to its proven ability to lower insulin resistance. In one example of this, researchers from the University of Alabama conducted a small study on a group of obese men with prediabetes. They compared the effects of restricting eating to an eight-hour period of the day (7 a.m. to 3 p.m.) or spread out over 12 hours (between 7 a.m. and 7 p.m.). The results showed that while both groups maintained the same weight after five weeks, the 8-hour eating window group had dramatically lower insulin levels and significantly improved insulin sensitivity. (3)  

4. Better mood control 

Fasting may be able to directly influence mood. How? Studies have shown that fasting can have antidepressant effects, which may be explained by an increase tryptophan, serotonin and, endorphins (which are two important feel-good chemicals in the brain), and BDNF, which is one of the factors involved in the activity of antidepressants. (4) This is a benefit I hear about from my patients and followers all the time, and one that I’ve experienced in my own life firsthand! Achieving more metabolic flexibility can help reduce blood sugar ups and downs, which can cause shakiness, crankiness, and “hanger.” 

5. Steadier energy levels 

Intermittent fasting puts your body into ketosis, which means you start burning fat for fuel instead of sugar. Ketosis has also been shown to increase mitochondria biogenesis, which just means the making of new mitochondria. (5) If you’ve never heard of the mitochondria before, they’re known as the “energy centers” of your cells. They are what allow us to take the food we eat and turn the nutrients into a specific form of energy (called ATP) that fuels our body.  The healthier our mitochondria, the more energy we have. 

6. A healthier heart 

Heart disease is the number one cause of death worldwide and affects millions of people every single day. And here’s the thing: Many forms of cardiovascular disease can be prevented by healthy lifestyle factors like proper nutrition, exercise, stress reduction, and yes — fasting! Fasting can benefit the cardiovascular system, especially when it comes to risk factors such as unhealthy cholesterol markers, high blood pressure, and unhealthy levels of triglycerides. For example, one observational study showed that those who routinely fasted (as part of religious practice or for another reason)  were less likely to have clogged arteries or coronary artery disease; the same study showed that fasting also led to higher levels of “good” cholesterol (called HDL cholesterol) and lowering levels of inflammatory “bad” cholesterol particles (called LDL cholesterol). (6)

7. Increased efficacy of chemotherapy 

I’ll end on another incredible emerging benefit — fasting during chemotherapy treatment. This might seem strange, but it’s being studied widely with really exciting results, For example, short-term fasting during chemotherapy treatment increases the efficacy of chemotherapy and reduces its many side effects. (7) The way this works is pretty awesome: fasting increases the stress resistance of healthy cells, protecting them from the chemotherapy drug, while simultaneously making tumor cells even more vulnerable to chemotherapeutic agents. Many scientists feel that fasting during chemotherapy is a feasible way to enhance the efficacy and tolerability of chemotherapy drugs. 

As you can see from the seven items above, fasting is about way more than just weight loss. Fasting is about longevity, energy, digestion, and happiness, not weight loss and restriction. In fact, I see intermittent fasting as a way to break free of diet culture and show your body with some extra love and care so that you feel good. That’s what it’s all about, isn’t it? 

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    1. Kanazawa M, Fukudo S. Effects of fasting therapy on irritable bowel syndrome. Int J Behav Med. 2006;13(3):214-20. doi: 10.1207/s15327558ijbm1303_4. PMID: 17078771.
    2. Mattson MP, Moehl K, Ghena N, Schmaedick M, Cheng A. Intermittent metabolic switching, neuroplasticity and brain health [published correction appears in Nat Rev Neurosci. 2020 Aug;21(8):445]. Nat Rev Neurosci. 2018;19(2):63-80. doi:10.1038/nrn.2017.156
    3. Jamshed H, Beyl RA, Della Manna DL, Yang ES, Ravussin E, Peterson CM. Early Time-Restricted Feeding Improves 24-Hour Glucose Levels and Affects Markers of the Circadian Clock, Aging, and Autophagy in Humans. Nutrients. 2019;11(6):1234. Published 2019 May 30. doi:10.3390/nu11061234
    4. As it turns out, fasting may also directly influence mood in a positive way; in fact, studies have shown that fasting can have antidepressant effects, which may be explained by an increase in neuronal autophagy (which is just autophagy of the brain cells), tryptophan, serotonin and, endorphins (which are two important feel-good chemicals in the brain), and BDNF, which is one of the factors involved in the activity of antidepressants.   
    5. Hasan-Olive MM, Lauritzen KH, Ali M, Rasmussen LJ, Storm-Mathisen J, Bergersen LH. A Ketogenic Diet Improves Mitochondrial Biogenesis and Bioenergetics via the PGC1α-SIRT3-UCP2 Axis. Neurochem Res. 2019 Jan;44(1):22-37. doi: 10.1007/s11064-018-2588-6. Epub 2018 Jul 19. PMID: 30027365.
    6. Rothschild J, Hoddy KK, Jambazian P, Varady KA. Time-restricted feeding and risk of metabolic disease: a review of human and animal studies. Nutr Rev. 2014 May;72(5):308-18. doi: 10.1111/nure.12104. Epub 2014 Apr 16. PMID: 24739093.
    7. de Groot S, Pijl H, van der Hoeven JJM, Kroep JR. Effects of short-term fasting on cancer treatment. J Exp Clin Cancer Res. 2019;38(1):209. Published 2019 May 22. doi:10.1186/s13046-019-1189-9

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Dr. Will Cole, DNM, IFMCP, DC is a leading functional medicine expert who consults people around the globe, starting one of the first functional medicine telehealth centers in the world. Named one of the top 50 functional and integrative doctors in the nation, Dr. Will Cole provides a functional medicine approach for thyroid issues, autoimmune conditions, hormonal imbalances, digestive disorders, and brain problems. He is the host of the popular The Art Of Being Well podcast and the New York Times bestselling author of Intuitive Fasting, Ketotarian, The Inflammation Spectrum and the brand new book Gut Feelings: Healing the Shame-Fueled Relationship Between What You Eat and How You Feel.

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Gut Feelings

Healing The Shame-Fueled Relationship
Between What You Eat And How You Feel