Fasting benefits and the benefits of intermittent fasting have become well known. In fact studies show that fasting can boost heart-health, gut-health, brain-health, and longevity. It’s a go-to for weight loss, disease mitigation, and mental health. And for some folks, including researchers, a way of life.
If you’ve ever wondered if fasting is good for you, you’re not alone. I found myself wondering the same thing many decades ago when I first took it up. Working out on an empty stomach, I found, boosted performance and gave me an epic vibe. Then along came three-day, five-day, then seven-day fasts, and I was rocking!
One of the key reasons it’s so beneficial is because it gives your body a break from digestion. Normally, your digestive tract is busy, processing meals and snacks throughout the day. But when you fast, you allow your body to shift toward other important tasks like cellular repair, detoxification, and energy conservation.
The process reduces inflammation, oxidative stress, and high blood pressure, while boosting immunity, insulin sensitivity, and the microbiome. In fact caloric restriction alone has been shown to extend lifespan by over 30%.
Autophagy
In 2016, when Yoshinori Ohsumi won the Nobel Prize in Medicine for illuminating autophagy—how cells revive—the benefits of fasting and intermittent fasting became better know. In fact according to Nature, autophagy repairs damaged cells, crushes pathogens, and preserves homeostatic balance that helps offset disease.
So on top of reducing metabolic disorders, neurodegenerative diseases, cancers, infectious diseases, and more, fasting triggers apoptosis—a clearing house for pre-cancerous cells. One doctor notes that fasting can “protect organs against chronic diseases like type 2 diabetes, heart disease, age-related neurodegenerative disorders, even inflammatory bowel disease and many cancers.”
So it’s little wonder it’s become a leading strategy for bolstering health.
What Is Fasting?
Fasting refers to the voluntary abstinence from food and, in some cases, beverages, for a specific period, triggering metabolic and physiological adaptations in the body. During fasting, glycogen stores are depleted, leading to a metabolic shift where the body breaks down fats for energy and produces ketones in a process called ketosis.
Ketosis occurs when molecules called ketones are made in the liver when your body’s short on glucose. It functions as a metabolic fuel that burns fat for energy. One report notes that “A growing body of evidence suggests that in the absence of ready supplies of glucose and fats from meals, fasting flips a metabolic “switch,” liberating fat stores via fatty acid oxidation and ketone production while prioritizing the safeguarding of lean muscle mass and function.”
Hormesis & Ketosis During Fasting
Hormesis during fasting occurs when the body experiences mild stress due to the temporary lack of food intake, triggering adaptive responses that enhance cellular repair, resilience, and longevity. This stress stimulates pathways like autophagy, antioxidant production, and mitochondrial biogenesis, making cells more efficient and resistant to future stressors.
While ketosis can also occur during fasting, it’s a distinct metabolic process where the body shifts from using glucose to burning fat, producing ketone bodies for energy. Unlike hormesis, which is a cellular stress adaptation, ketosis is a metabolic state aimed at energy preservation. Though both processes often overlap during fasting, hormesis is about strengthening cellular function, whereas ketosis is about fuel utilization.
Both contribute to the physiological health benefits of fasting.
15 Benefits of Fasting
Below is a science-backed list of 12 benefits of fasting:
1. Promotes Autophagy
- Fasting triggers autophagy, a process where cells remove damaged components and recycle them, potentially reducing the risk of diseases like Alzheimer’s and cancer.
- Study: Yoshinori Ohsumi (2016 Nobel Prize in Medicine) – Autophagy in cellular homeostasis and disease (Nature, 2018).
2. Enhances Brain Function
- Intermittent fasting increases brain-derived neurotrophic factor (BDNF), supporting cognitive function and lowering the risk of neurodegenerative diseases.
- Study: Mattson MP et al. – Intermittent metabolic switching, neuroplasticity, and brain health (Nature Reviews Neuroscience, 2018).
3. Supports Weight Loss & Fat Burning
- Fasting increases fat oxidation and boosts metabolism by enhancing norepinephrine levels, aiding in weight loss.
- Study: Tinsley GM & La Bounty PM – Effects of intermittent fasting on body composition and clinical health markers in humans (Nutrients, 2015).
4. Improves Insulin Sensitivity & Lowers Blood Sugar
- Fasting reduces insulin resistance, helping lower blood sugar levels and potentially preventing type 2 diabetes.
- Study: Sutton EF et al. – Early time-restricted feeding improves insulin sensitivity, blood pressure, and oxidative stress (Cell Metabolism, 2018).
5. Reduces Inflammation & Oxidative Stress
- Fasting lowers inflammatory markers like CRP and IL-6, reducing the risk of chronic inflammatory diseases.
- Study: de Cabo R & Mattson MP – Effects of intermittent fasting on health, aging, and disease (New England Journal of Medicine, 2019).
6. Lowers Risk of Heart Disease
- Fasting improves cholesterol levels, blood pressure, triglycerides, and other cardiovascular markers.
- Study: Horne BD et al. – Intermittent fasting and markers of cardiovascular risk (American Journal of Cardiology, 2008).
7. Lifespan Extension
- Fasting activates longevity genes and mimics the effects of calorie restriction, which has been shown to extend lifespan in various species.
- Study: Fontana L & Partridge L – Promoting health and longevity through diet: from model organisms to humans (Cell, 2015).
8. Boosts Human Growth Hormone
- Fasting increases HGH levels significantly, aiding in muscle growth, fat loss, and metabolism.
- Study: Ho KY et al. – Fasting enhances growth hormone secretion (New England Journal of Medicine, 1988).
9. Supports Gut Health & Microbiome Diversity
- Fasting gives the digestive system a break, promotes gut healing, and fosters a healthier microbiome.
- Study: Thaiss CA et al. – The microbiome and metabolic health during fasting (Cell Metabolism, 2016).
10. May Reduce Cancer Risk
- Fasting slows tumor growth and enhances medical treatments by making cancer cells more susceptible. However it’s important to eat healthy organic food during the refeeding period, such as raw veggies, salads, berries, etc. Light and clean.
- Study: Brandhorst S et al. – Fasting-mimicking diet and reduced IGF-1 levels in cancer therapy (Science Translational Medicine, 2016).
11. Improves Mental Clarity & Mood
- Fasting increases ketone production, which provides a steady source of energy for the brain and improves mood stability.
- Study: Witte AV et al. – Caloric restriction enhances memory performance in healthy elderly subjects (PNAS, 2009).
12. Enhances Immunity
- Fasting promotes stem cell regeneration of the immune system, improving immune function and overall health.
- Study: Cheng CW et al. – Prolonged fasting reduces IGF-1 and promotes hematopoietic-stem-cell-based regeneration (Cell Stem Cell, 2014).
13. Deepens Spiritual Connection
- Fasting has been practiced for centuries in various spiritual traditions as a means to cultivate mindfulness, gratitude, and inner peace. By stepping away from physical indulgences, individuals often report a heightened sense of awareness, deeper meditation, and a stronger connection to their faith or personal values.
- Study: Walsh R. – Meditation research: The state and future of the art (Int J Psychophysiol,1984).
14. Reduces Anxiety & Enhances Resilience
- Fasting helps regulate neurotransmitters such as serotonin and dopamine, leading to reduced anxiety, greater emotional stability, and improved stress tolerance. The discipline involved in fasting can also build psychological resilience, making it easier to cope with life’s challenges.
- Study: Ayyad C et al. – The impact of intermittent fasting on mood, cognition, and psychological well-being (Nutr Neurosci, 2021).
15. Boosts Mindfulness
- Fasting encourages a heightened awareness of bodily sensations, emotions, and thought patterns, fostering a deeper sense of mindfulness. By removing constant food consumption as a distraction, individuals become more attuned to their hunger cues, eating habits, and emotional triggers, leading to a more conscious and intentional way of living.
- Tang YY et al. – The neuroscience of mindfulness meditation (Nat Rev Neurosci, 2015).
Fasting Health Benefits
FAQ
1. Does Fasting Include Water?
Traditionally most fasts are only water, but it’s possible to obtain benefits from extended juice cleansing, coffee and tea fasts, and infused liquids. However it won’t produce the same results as water fasting due to all the nutrients onboard. They require digestion that water alone does not.
Raw organic juices, lemon water, and broths are a great way to work into a fast—or a strategy of caloric restriction overall.
2. Is Fasting Good For High Blood Pressure?
Fasting has been shown by numerous peer-reviewed studies to reduce high blood pressure. It balances the endocrine system and enhances parasympathetic activity while reducing inflammation and boosting arterial health. According to one report, it’s the single most effective way to curb hypertension:
“The single most effective way to lower hypertension is the practice of fasting. A two-week period of medically supervised, water-only fasting resulted in blood pressure readings below 120/80 mm Hg in 82% of subjects with borderline hypertension (Goldhamer et al., 2002).”
Other studies also support the benefits of fasting for high BP: “In humans, intermittent fasting can reduce blood pressure, oxidative stress, and the risk of atherosclerosis. One month of alternate-day fasting effectively lowers blood pressure and heart rate in healthy nonobese humans, suggesting that chronic fasting may enhance parasympathetic activity.”
According to the American Heart Association, “Long‐term fasting tends to decrease BP in subjects with elevated BP values. This effect persisted during the 4 days of stepwise food reintroduction, even when subjects stopped their antihypertensive medication.”
3. Is Fasting Good For Diabetes?
Fasting can be good for diabetes because it reduces insulin resistance and can help you lose weight. It also curbs fat-intake, a major contributor to diabetes. According to one report, “Type 2 diabetes can now be understood as a state of excess fat in the liver and pancreas, and remains reversible for at least 10 years in most individuals. . . . With the loss of 15 percent of body weight, nearly 90 percent of those who’ve had type 2 diabetes for less than four years can achieve remission, whereas it may only be reversible in 50 percent of those who’ve lived with the disease for longer than eight years.”
When people fast and stop eating fatty foods, their blood glucose drops. When they eat a plant-based diet combined with fasting and exercise, it’s a win. But with one caveat: “An extended bout of physician-supervised, water-only fasting could get you there, but you have to maintain that weight loss. One of the things we can say with certainty is that if you regain the weight, you regain your diabetes.”
4. How Does Fasting Help Inflammation?
Studies have shown that fasting reduces inflammation and helps improve inflammatory diseases. It curbs the release of pro-inflammatory cells called ‘monocytes.’ Subjects who are well fed have higher levels of circulating monocytes than fasted subjects.
According to this report: “In a study published in Cell, Mount Sinai researchers found that fasting reduces inflammation and improves chronic inflammatory diseases without affecting the immune system’s response to acute infections.” Another source notes that “Fasting and caloric restriction have a potential means of anti-inflammatory, as they can decrease the level of systemic inflammation.”
5. Does Fasting Improve Cholesterol?
Fasting has been shown by numerous studies to improve cholesterol. It causes a metabolic shift that triggers ketosis, autophagy, and hormesis. Participants in one study experienced a decrease in LDL and increase in HDL cholesterol after fasting (i.e., less bad cholesterol, more good). It also curbs triglycerides and boosts insulin sensitivity.
According to one report, “Studies have shown that alternate-day fasting over 8 to 12 weeks causes decreases in LDL cholesterol concentrations (20-25%) and triacylglycerol concentrations (15-30%), and increases in LDL particle size are often observed. Similarly, alternate-day fasting trials of a 3- to 12-week duration appear to be effective at reducing total cholesterol (10%–21%) and triglycerides (14%–42%) in normal-weight, overweight, and obese humans.”
6. Is Fasting Good For Your Heart?
Fasting can be incredibly good for your heart. Studies have shown it boosts a protein called galectin-3 that reduces inflammation. It helps prevent cardiovascular disease by mitigating obesity, high blood pressure, inflammation, and type 2 diabetes. It also reduces oxidative stress and boosts arterial function.
7. Can Fasting Treat Serious Disease?
Studies have suggested that water fasting, and particularly in combination with a sugar-free, oil-free, plant-based diet, can potentially slow and even reverse disease. That’s because fasting boosts the immune system and in many cases increases the activity of Natural Killer cells and apoptosis (cancer cell death).
However please keep in mind that it’s important to consult your physician regarding matters of serious and chronic disease.
8. Can Fasting Promote Weight Loss?
So it almost seems like a no-brainer that you’d lose weight during fasting or intermittent fasting, right? I mean with such a reduction in calories, how could you not? Well fasting, in my experience, is one of the quickest and most effective ways to jumpstart a weight loss plan. I’ve done it many times across the years and watched others do it too.
One report notes that “A systematic review of 40 studies found that intermittent fasting was effective for weight loss, with a typical loss of 7-11 pounds over 10 weeks.”
I personally suggest you taper into and out of fasts gradually, working your way from raw organic veggies and soups on down to clear broths and juices before full withdrawal from food. And work out in a similar fashion. If you have medical conditions and/or take prescription drugs you should consult your physician before fasting. It’s a simple enough routine but can be dangerous for some people and cause lean muscle loss if done incorrectly.
9. Is Juice Fasting Effective?
Juice fasting, and especially with raw organic vegetable juice, is immensely healthy because it reduces calories while providing tons of enzymes and phytonutrients. In fact one report notes that “Juice fasting can be just as effective as water and simultaneously nourishes and strengthens the body rather than depleting and weakening it.”
So traditionally, even though an ‘authentic’ fast is considered to be nothing but water, you can still obtain benefits from a juice cleanse. Author Steve Meyerwitz says this: ”Juice fasting with wheatgrass and raw vegetable juices introduces oxygen and nutrients into the bloodstream while enhancing elimination.”
10. Does Fasting Slow Metabolism?
Studies have shown that short fasts and intermittent fasting can boost metabolism by over 13%. It increases fat-burning hormones like norepinephrine and resting energy expenditure.
11. Does Simple Calorie Cutting Help?
According to one report, “A new scientific study has backed up some health claims about eating less. The clinical trial reveals that cutting back on food for just 5 days a month could help prevent or treat age-related illnesses like diabetes and cardiovascular disease.”
12. Is Fasting Bad For the Liver?
On the contrary, studies have shown that fasting reduces liver weight, enhances liver metabolism, and boosts liver enzymes. According to Dr. Mark Larance, “We know that fasting can be an effective intervention to treat disease and improve liver health.”
The Healing Crisis
The healing crisis, also known as the Herxheimer reaction or detox reaction, is the body’s natural response to deep internal cleansing. When fasting, the body shifts from digestion to repair mode, breaking down damaged cells and releasing stored toxins.
This rapid detoxification can overwhelm the system temporarily, leading to symptoms that may feel like illness—headaches, fatigue, nausea, body aches, brain fog, and even flu-like symptoms. While uncomfortable, these effects are not signs of harm but rather proof that the body is eliminating years of accumulated waste.
This process occurs because, during fasting, fat stores—where toxins are often trapped—begin to break down, flooding the bloodstream with impurities on their way out. The liver, kidneys, and intestines work hard to filter and expel these toxins, but the sheer volume can lead to temporary discomfort.
This phase is often mistaken for fasting “not agreeing” with the body, but in reality, it’s the body adjusting to a higher state of health. As the detox phase passes, energy levels rise, mental clarity sharpens, and overall well-being improves—marking the transition from cleansing to true rejuvenation.
John Hopkins explains that “it can take two to four weeks before the body becomes accustomed to intermittent fasting. You might feel hungry or cranky while you’re getting used to the new routine.”
Dr. James Thompson calls it an “acute reaction of the body brought about by an improvement of the vital forces, enabling them to eliminate from the system the diseased conditions and accumulations.”
Fasting & Children
Due to children’s developmental and nutritional needs, they typically don’t need to fast unless they’re unhealthily overweight. And even then a change to an organic plant-based diet with lots of raw veggies and fruits should do the trick without skipping meals, and especially with exercise and low/no sugar.
Overweight children sometimes get that way due to diets high in processed foods, sugary drinks, and unhealthy snacks. More often than not their weights will naturally adjust with a cleaner, healthier diet and monitored eating.
Side Effects & Cautions
While fasting offers numerous health benefits, it is not without potential side effects and risks. Common short-term effects include hunger, fatigue, irritability, headaches, and dizziness, especially for beginners. Prolonged or extreme fasting can lead to nutrient deficiencies, muscle loss, and weakened immune function.
Individuals with diabetes, low blood pressure, eating disorders, or those who are pregnant or breastfeeding should consult a healthcare professional before attempting fasting. Additionally, fasting may affect medication absorption and blood sugar levels, requiring careful monitoring.
To minimize risks, it’s essential to stay hydrated, break fasts gradually, and choose a fasting method that suits individual needs.
Historical Touchstones
Fasting has played a significant role throughout history, valued for its healing, spiritual, and cultural importance. Hippocrates, the father of Western medicine, believed that fasting enabled the body to heal itself, while Paracelsus, a Renaissance physician, called it “the physician within.”
In ancient Greece, Pythagoras extolled its virtues, and Ayurvedic medicine has long advocated fasting as a major treatment. Its benefits were noted long ago by Mark Twain’s famous words: “A little starvation can really do more for the average sick man than can the best medicines and the best doctors.”
Nowadays, fasting has become a widely popular and efficacious routine for boosting overall health. 💚
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The medical and health topics covered on the Plate of Grass website and blog have not been evaluated by the FDA and are not intended to prevent or cure any disease. This article and its content is presented ‘as is’ for informational purposes only.
