Overview
Fasting is the abstinence from all or some foods and drinks for a specified period of time. For centuries, it has played a major role in many cultures and religions.
Considering that fasting has numerous health benefits, including weight loss, it has become one of the many popular health and fitness trends in the world.
Fasting can be done in various ways, but most types of fasting are performed over 24–72 hours.
Types of Fasting
There are different types of fasts, and the most common types include the following:
Water Fasting
This type of fast involves only drinking water for a specified amount of time.
Juice Fasting
This type of fast involves only drinking fruit or vegetable juice for a certain period.
Intermittent Fasting
A type of fast in which intake is either partially or completely restricted for a few hours up to a few days and resuming a normal diet on other days. There are several intermittent fasting benefits.
Partial Fasting
A type of fast in which certain foods or drinks such as animal products, processed foods, or caffeine are eliminated from the diet for a specified period of time.
Calorie Restriction
From the word itself, this is a type of fast in which calorie intake is restricted for a few days every week.
Fasting Benefits
Fasting has been known to have various health benefits, such as increased weight loss and improved brain function. Here are 16 benefits of fasting backed by science.
1. It Significantly Affects your Cells and Hormones
With fasting, a lot of things happen in your body on the molecular and cellular level. That is, the body adjusts the hormone levels so the stored body fat becomes more accessible. The cells also initiate important repair processes and change the expression of genes.
2. It Promotes Blood Sugar Control
Fasting improves blood sugar control by reducing insulin resistance, which reduces the risk of diabetes.
A study in 10 people who have type 2 diabetes demonstrated that short-term intermittent fasting significantly reduced blood sugar levels.
As shown by another review, both alternate day fasting and intermittent fasting are as effective as limiting calorie intake at reducing insulin resistance.
Reduced insulin resistance increases the body’s sensitivity to insulin, which allows it to more efficiently transport glucose from your bloodstream to your cells.
With blood sugar-lowering effects of fasting, this could help keep your blood sugar steady, which prevents crashes and spikes in your blood sugar levels.
It is noteworthy that some studies have found that fasting differently impacts the blood sugar levels for men and women. For example, a small study showed that doing alternate day fasting had no effect in men but impaired blood sugar control in women.
3. It Promotes Better Health
Some studies suggest that by fighting inflammation, fasting promotes better health.
Acute inflammation is a normal immune process to help fight off infections, but chronic inflammation may have serious consequences for your health.
Research suggests that inflammation may have played a significant role in the development of chronic conditions, such as cancer, heart disease, and rheumatoid arthritis.
A study in 50 healthy adults demonstrated that 1-month intermittent fasting significantly decreased levels of inflammatory markers. And another small study of people who did fasting for 12 hours each day in 1 month also came up with a similar end result.
4. It Enhances Heart Health
By improving blood pressure, cholesterol levels, and triglycerides, fasting can enhance heart health.
Heart disease accounted for an estimated 31.5% of global deaths, making it the leading cause of death worldwide.
One of the most effective ways in reducing your risk of heart disease is switching up your lifestyle and diet. In fact, one research has found that including fasting in your routine is especially beneficial when it comes to heart health.
A small study showed that an 8-week alternate day fasting respectively reduced levels of blood triglycerides and “bad” LDL cholesterol by 32% and 25%.
Another study in 110 obese adults demonstrated that a 3-week fasting under medical supervision significantly reduced blood pressure, as well as levels of blood triglycerides, “bad” LDL cholesterol, and total cholesterol.
Moreover, a 4,629-people study linked fasting to a lower risk of coronary artery disease and a significantly lower risk of diabetes.
5. It Boosts Brain Function and Prevents Neurodegenerative Disorders
Although most research is limited to animal research, several studies found that fasting may prevent neurodegenerative disorders and boost brain function.
A study in mice demonstrated that practicing an 11-month intermittent fasting improved both brain structure and brain function.
As fasting is known to relieve inflammation, it may also prevent neurodegenerative disorders. In fact, animal studies have shown that fasting may protect against conditions like Parkinson’s and Alzheimer’s disease.
However, further research on fasting and human brain functions needs to be conducted.
6. It Promotes Better Concentration
As fasting has been known to protect the brain by improving its structure and function, it is more likely to result in better concentration. A 2018 study suggests that fasting protects against Alzheimer’s disease by reducing the incidence of memory loss.
But obviously, more research on the matter is needed to prove its efficacy in promoting better concentration.
7. It Aids Weight Loss
By limiting calorie intake and boosting metabolism, fasting is believed to aid weight loss. In fact, many people seeking a quick and easy way to drop a few pounds prefer fasting.
Basically, abstaining from all or certain foods and drinks should result in reduced calorie intake, which gradually leads to weight loss.
Additionally, by increasing levels of neurotransmitter norepinephrine, short-term fasting may also boost your metabolism.
In fact, a review demonstrated that fasting for a whole day decreases body weight by up to 9% and significantly reduces body fat in 12–24 weeks.
8. It Promotes Lower Cholesterol
A study in 2018 showed that people following a 5:2 diet had lower risk of heart disease as compared with people dieting by counting calories.
And this is one of the reasons why fasting is effective when it comes to weight loss.
9. It Increases Growth Hormone Secretion
Human growth hormone (HGH) is a type of protein hormone that is vital for growth, weight loss, metabolism, and muscle strength. Many studies have demonstrated fasting to naturally increase HGH levels.
A small study in 11 healthy adults showed that a 24-hour fast significantly increased HGH levels.
Another small study of 9 men showed that a 2-day fast led to a 5-fold increase in the HGH production rate.
What’s more, fasting helps maintain steady blood sugar and insulin levels, which may further enhance HGH level, as some research has shown that sustaining increased levels of insulin reduces levels of HGH.
10. It Delays Aging and Extends Longevity
Some animal studies have found that fasting has potential lifespan-extending effects. In fact, a study in rats fasted every other day (alternate day fasting) experienced a delayed rate of aging and therefore lived 83% longer compared with rats that didn’t fast.
Some animal studies have come up with similar results, indicating that fasting can effectively increase longevity and survival rates.
Studies showed that rats on intermittent fasting lived 36–83% longer, thereby extending the lifespan in rats.
Unfortunately, these research are limited to animal studies. Further human studies are needed to fully comprehend how fasting affects longevity and aging in humans.
11. It Aids in Cancer Prevention and Increases the Effectiveness of Chemotherapy
Fasting to restrict calories decreases IGF-1 levels and may result in slower tumor development.
Based on a review in 2019, cancer patients discovered that fasting reduces some of the chemotherapy side effects and therefore increases its effectiveness. The study authors suggested that cancer cells may be deprived with nutrients by way of fasting, which makes them susceptible to chemotherapy toxins.
Animal and test-tube studies have shown that fasting benefits the prevention and treatment of cancer. In a rat study, it has been indicated that alternate day fasting helped block tumor formation.
Moreover, a test-tube study indicated that fasting is as effective as chemotherapy in delaying tumor growth, and thus increases the effectiveness of chemotherapy drugs on cancer formation.
However, most research is limited to animal studies. Further research on the effects of fasting on cancer formation in humans is required.
12. It Promotes Better Sleep
Some small research has demonstrated that late night eating disrupts sleep or causes sleep disturbances.
Fasting most likely eliminates late night eating as it has a specified eating period.
13. It Promotes Mindful Eating Habits
Fasting promotes mindful eating as it forces you to establish specific eating windows. It eliminates your absent-minded noshing and helps you control your calorie intake.
14. It Promotes Better Immunity
Fasting proponents claimed that restricting your calorie intake can reset your immune system.
A study in the University of Southern California on both mice and humans suggested that a 72-hour fast allows your body to flush out damaged immune cells and stimulate new, healthier cells that will help the body in fighting toxins.
15. It Reverses Diabetes
Diabetes can be managed by medication, exercise, and diet. According to the researchers in the University of California, fasting can stop the disease in its track. The study indicated that a fasting-like diet triggers the production of new pancreatic cells to replace dysfunctional ones, controls blood sugar, and reverses insulin depletion and resistance.
16. It Promotes Clearer Skin
What we eat affects our skin health. According to the American Academy of Dermatology, certain foods, such as white bread, milk, and sugary snacks, increase acne by spiking your blood sugar.
With fasting, you get to carefully choose what to eat during the eating periods, making sure that you are eating healthy foods.
Safety and Side Effects of Fasting
Despite the long list of possible health benefits of fasting, it is still not good for everyone.
Fasting is not recommended for pregnant and lactating women, people who are underweight and have underlying health condition/s, and for older adults without medical supervision.
The best thing to do when you decide to try fasting is to talk to your doctor first for better recommendations. And as you start fasting, make sure to fill your diet with foods rich in nutrients during your eating periods and stay well-hydrated to maximize the potential health benefits.
Moreover, minimize intense physical activities if your fasting plan lasts for longer periods.
Conclusion
Fasting has got a number of health benefits. It significantly affects your cells and hormones, promotes blood sugar control, promotes better health, enhances heart health, boosts brain function and prevents neurodegenerative disorders, promotes better concentration, aids weight loss, promotes lower cholesterol, increases growth hormone secretion, delays aging and extends longevity, aids in cancer prevention and increases the effectiveness of chemotherapy, reverses diabetes, promotes better sleep, mindful eating habits, better immunity, and clearer skin.
However, despite all these potential health benefits, it can have adverse effects for some people, especially those who are underweight and older adults and those who have underlying health conditions, as well as pregnant and lactating women. Fasting for children may not be a good idea as well.
