Fasting has been recognized for its many health benefits dating back to Hippocrates. These benefits extend to everything from better weight management, improved cardiovascular health, healthier blood composition, and better cell recycling, among many others.

Although there is not an abundance of research on fasting in humans, a growing number of health experts believe that the results of fasting from animal studies hold great promise for human health and future research efforts.

There are many different types of fasts you can choose from, and they differ in their results and difficulty. Much of the research included here comes from studies on caloric restriction and intermittent fasting. One conclusion is steadfast, fasting remains one of the most effective means of detoxifying your body and resetting your system for better overall health.

20 Health Benefits of Fasting

1. Improves Body Composition and Fitness

People fast for all kinds of reasons, and many are particularly interested in the effects fasting has on the body’s fat tissues and overall weight loss. Others fast or intermittently fast for better exercise results. Fasting contributes to a better body composition in several ways, primarily through its actions on hormones and fat metabolism.

2. Promotes Greater Satiety

Your fatty tissue acts as a kind of endocrine organ, producing several different hormones. One of these hormones, leptin, affects how full you feel. Fasting and weight loss significantly affect your hunger level and post-meal satisfaction through this hormone. With fasting, leptin levels drop initially, but as you lose weight, you decrease leptin resistance. Becoming more responsive to leptin signals increases how full you feel.[1]

3. Boosts Your Metabolism

Leptin, though known primarily as the “satiety” hormone, also increases thyroid hormone production. Improved leptin sensitivity increases the rate of your metabolism if you have a sluggish thyroid.[1]

4. Supports Fat Loss and Ketosis

Ketosis, or the fat-burning state, is reached either by fasting or eating a diet centered on healthy fats. Ketosis helps you burn through your fat reserves. Excessive central fat stored around organs, like your liver and kidneys, interferes with organ function. Fasting, particularly intermittent fasting, helps you reach ketosis even faster than traditional caloric restriction. One study found that fasting significantly boosted fat metabolism in humans.[1, 2, 3]

5. Encourages Better Insulin Sensitivity

Fasting causes the body to secrete less insulin because you’re not giving yourself steady doses of sugar. Lower levels of this hormone lead to increased sensitivity in those with insulin resistance. Excessive fat stores seem to contribute to this resistance. Some research points to excessive fat in the body, blood, and diet as a contributor to insulin resistance by preventing it from doing its job, i.e., opening the pores on your cell membranes to allow sugar to pass into them.[4, 5]

6. Improves Cardiovascular Health

One of the main benefits of fasting, particularly for people that have metabolic syndrome-related health concerns, is the many immediate cardiovascular benefits. Fasting improves cardiovascular function, blood composition, and blood pressure. Those with type 2 diabetes or high cholesterol may find fasting helpful for addressing some of the associated health concerns.[6]

7. Lowers Blood Pressure

While fasting, many people develop lower blood pressure, primarily during the first week of a fast. It might not be fasting itself that decreases blood pressure, but rather a significantly lower salt intake and increased loss of salt through the urine.[7]

8. Decreases Blood Sugar

In just the first few days of fasting, blood sugar drops over 30%, a significant perk to anyone with hyperglycemia. This drop usually makes people feel low energy, but your blood sugar levels should stabilize as you continue to fast.[2]

9. Improves Blood Triglycerides

Blood triglycerides decrease during the fasting state. Having fatty blood increases your risk of developing narrowed arteries.[2]

10. Promotes Heart Health

Another animal study found that fasting leads to improved heart health. In animals, researchers found that intermittent fasting improved heart muscle performance, reduced free radical damage, and increased the growth of blood vessels within the heart.[2]

11. May Slow Aging and Enhance Longevity

Research into fasting for longevity and healthier aging is well-established in animals, but controlled testing on humans is still in its infancy. Better blood composition alone improves healthier aging and health outcomes. The effects of fasting appear to lead to a healthier, longer lifespan.[8]

12. Decreases Inflammation

Inflammation has many causes, but an unhealthy diet is a consistent source of free radicals and the foods that cause inflammation. Refined sugar, refined carbs, alcohol, meat, dairy, and fried or charred foods provoke inflammation. But food isn’t the only source—metabolic reactions also generate free radicals like superoxides and hydrogen peroxide. Foregoing a few meals prevents food-related inflammation before it even starts.[9]

Another way that fasting decreases inflammation is through better hormone balance. Several studies have found lower insulin levels and improved insulin sensitivity decrease oxidative stress caused by free radicals.[8, 9]

13. Increases Resistance to Oxidative Stress

Free radical-related damage is a well-known contributor to premature aging. The benefits of fasting include better blood composition, improved hormone signaling, less oxidative stress, and healthier gene signaling. These benefits make your body’s oxidative stress plummet, a feat that keeps your genes, cells, and tissues healthy as you age.[2, 10]

14. Improves Cell Recycling

As we age, rogue cells, both human and foreign, can proliferate throughout the body unchecked and this damaged tissue can contribute to progressive disease. Fasting sends your body into cell recycling, a process of self-digestion at the cellular level called autophagy. But you’re not just digesting your fat to fuel yourself while fasting. Your body also targets malfunctioning cells and old tissues to optimize resources for survival.[11]

Fasting promotes the destruction of malfunctioning cells and tissues through selective protection. It selectively protects healthy tissues because they respond to adverse conditions like famine or fasting.[12]

15. Increases Growth Regulation

Your body produces less IGF-1 (insulin-like growth factor 1) while fasting and on certain diets, such as a healthy plant-based diet. IGF-1 has been implicated as a hormone that helps cancer proliferate throughout the body. Reduced IGF-1 production decreases your odds of intractable tumor growth and spread. This means that fasting can help cleanse the body of not only the resources rogue cells need but also the hormones that help them stick around and thrive.[4]

16. Protects Your Brain

Studies on aging and brain function have substantially increased in the last decade. Life expectancies have increased well past what was once even thought possible. The public’s profound interest in brain health throughout all stages of life reflects a desire to age gracefully, healthfully, and with full mental faculties intact. Fortunately, fasting seems to specifically kickstart protective mechanisms in your brain.[1]

17. Reduces Harmful Protein Production

There are many proteins and metabolic products that provoke inflammation, particularly in the brain. Fasting and calorie restriction inhibit the production of free radicals and irritating proteins like inflammatory cytokines. Mounting evidence indicates that these contribute to premature brain aging and that fasting can decrease their production, protecting you from their impact. Interestingly, mounting evidence suggests that not only does free radical damage and inflammatory cytokine production slow down, but protective cytokine production increases while fasting.[1]

18. Promotes a Healthy Stress Response

Mild, infrequent stress is good for you. It challenges your body, and you come out stronger after going through it. Moderate, short stress on the brain produces a similar result. Fasting exerts a small amount of stress on the brain. This stress sets of a cascade of actions that protect neurons from damage and death in animal models.[1]

19. Enhances Recovery From Injury

You would think that fasting after injury, especially one to the glucose-hungry brain, would make recovery even more difficult. But the opposite seems to be true. In animal studies, intermittent fasting after injury improved brain function from stroke and diseases that affect the brain. At this time, the mechanism is not yet understood, so further investigation is required before your health care practitioner can start recommending intermittent fasting for recovery.[1]

20. Supports Healthier Collagen in Skin

Your diet is important to your skin’s appearance, but fasting can also improve your skin’s integrity. High blood sugar changes the structure of collagen, weakening its strength and resilience. Since fasting substantially lowers blood sugar, you can think of it as a normal part of your skin care routine to ensure graceful aging.[13]

Fasting for Health and Wellness

Research is still emerging in humans in some areas, but fasting has demonstrated so many potential benefits that you may find yourself wondering how to get started. I recommend you try my ketogenic fast if you’re looking to kick-start your weight loss journey and invest your fasting efforts into one of the most effective methods of organ and body cleansing.