Intermittent fasting is an eating pattern where you cycle between eating and fasting periods.
There are many different types of intermittent fasting, such as the 16/8 and 5:2 methods.
Numerous studies show that you can have important benefits for your body and brain.
Here are 10 evidence-based health benefits of intermittent fasting.
1. Changes the function of hormones, cells and genes
When you don’t eat for a period of time, several things happen in your body.
For example, your body changes hormone levels so that stored body fat is more accessible and initiates important cellular repair processes.
Here are some of the changes that occur in your body during fasting:
- Insulin levels. Insulin levels in the blood drop significantly, making it easier to burn fat.
Human growth hormone (HGH) levels. Blood levels of human growth hormone (HGH) can increase dramatically. Higher levels of this hormone make it easier to burn fat and build muscle, and have many other benefits.
- Cell repair. The body induces important cell repair processes, such as removing waste from cells.
- Gene expression. There are beneficial changes in several genes and molecules related to longevity and protection against disease.
Many of the benefits of intermittent fasting are related to these changes in hormones, cell function, and gene expression.
2. It can help you lose weight and visceral fat
- Many of the people who try intermittent fasting do so to lose weight.
- In general, intermittent fasting will cause you to eat fewer meals.
- Unless you compensate by eating much more during other meals, you will end up consuming fewer calories.
- Additionally, intermittent fasting improves hormonal function to facilitate weight loss.
- Lower levels of insulin, higher levels of HGH, and higher amounts of norepinephrine (noradrenaline) increase the breakdown of body fat and make it easier to use for energy.
- For this reason, short-term fasting actually increases your metabolic rate, helping you burn even more calories.
- In other words, intermittent fasting works both ways in the caloric equation. Increase your metabolic rate (increase calories) and reduce the amount of food you eat (reduce calories).
- According to a 2014 review of the scientific literature, intermittent fasting can cause 3 percent to 8 percent weight loss in 3 to 24 weeks. This is a large amount.
- Study participants also lost between 4 percent and 7 percent of their waist circumference between 6 and 24 weeks, indicating they lost a lot of visceral fat. Visceral fat is the harmful fat in the abdominal cavity that causes disease.
- A 2011 review also showed that intermittent fasting caused less muscle loss than continuous calorie restriction.
- However, a 2020 randomized trial looked at people who followed the 16/8 method. On this diet, you fast for 16 hours a day and have an 8-hour window to eat.
- People who fasted didn’t lose much more weight than those who ate three meals a day. After testing a subgroup of participants in person, the researchers also determined that the people who fasted lost a significant amount of lean mass. This included lean muscle.
- More studies are needed on the effect of fasting on muscle loss. All things considered, intermittent fasting has the potential to be an incredibly powerful tool for weight loss.
3. May reduce insulin resistance, lowering the risk of developing type 2 diabetes
Type 2 diabetes has become a very common diagnosis in recent decades.
Its main characteristic is high blood sugar levels in the context of insulin resistance.
Anything that reduces insulin resistance should help lower blood sugar levels and protect against type 2 diabetes.
Interestingly, intermittent fasting has been shown to have greater benefits for insulin resistance and cause an impressive drop in blood sugar levels.
In human studies on intermittent fasting, fasting blood sugar dropped by 3 percent to 6 percent over the course of 8 to 12 weeks in people with prediabetes. Fasting insulin dropped by 20 percent to 31 percent.
A study in mice with diabetes also showed that intermittent fasting improved survival rates and protected against diabetic retinopathy. Diabetic retinopathy is a complication that can cause blindness.
What this implies is that intermittent fasting may be highly protective for people who are at risk of developing type 2 diabetes .
However, there may be some differences between the sexes. A 2005 study in women showed that blood sugar management actually worsened after a 22-day intermittent fasting protocol.
4. May Reduce Oxidative Stress and Inflammation in the Body
Oxidative stress is one of the steps towards aging and many chronic diseases.
It involves unstable molecules called free radicals. Free radicals react with other important molecules, such as protein and DNA, and damage them.
Several studies show that intermittent fasting can improve the body’s resistance to oxidative stress.
Additionally, studies show that intermittent fasting can help fight inflammation, another key driver of many common illnesses.
5. May be beneficial for heart health
- Heart disease is currently the biggest killer in the world.
- Several health markers (so-called “risk factors”) are known to be associated with an increased or decreased risk of heart disease.
- Intermittent fasting has been shown to improve several different risk factors, including:
- blood sugar levels
- blood pressure
- blood triglycerides
- total and LDL (bad) cholesterol
- inflammatory markers
- However, much of this is based on animal studies.
- Further study of the effects of fasting on heart health in humans is needed before recommendations can be made.
6. Induces various cell repair processes
When we fast, the cells of the body initiate a cellular “waste removal” process called autophagy.
This implies that, over time, cells break down and metabolize broken and dysfunctional proteins that accumulate inside cells.
Increased autophagy may protect against several diseases, including cancer and neurodegenerative diseases, such as Alzheimer’s disease.
7. May Help Prevent Cancer
Cancer is characterized by the uncontrolled growth of cells.
Fasting has been shown to have several beneficial effects on metabolism that may reduce cancer risk.
Promising evidence from animal studies indicates that intermittent fasting or fasting-mimicking diets may help prevent cancer. Research in humans has had similar findings, although more study is needed.
There is also some evidence showing that fasting reduced various side effects of chemotherapy in humans.
8. It has benefits for your brain
- What’s good for the body is often good for the brain, too.
- Intermittent fasting improves several metabolic functions that are known to be important for brain health.
- Intermittent fasting helps reduce:
- oxidative stress
- the inflammation
- blood sugar levels
- insulin resistance
- Several studies in mice and rats have shown that intermittent fasting can increase the growth of new nerve cells, which should have benefits for brain function.
- Fasting also increases levels of a brain hormone called brain-derived neurotrophic factor (BDNF). A deficiency of BDNF has been implicated in depression and several other brain problems.
- Animal studies have also shown that intermittent fasting protects against brain damage due to stroke.
9. May help prevent Alzheimer’s disease
- Alzheimer’s disease is the most common neurodegenerative disease in the world.
- There is currently no cure available for Alzheimer’s, so preventing it from occurring is critical.
- Studies in rats and mice show that intermittent fasting can delay the onset of Alzheimer’s or reduce its severity.
- In a series of case reports, a lifestyle intervention that included short-term daily fasts was able to significantly improve Alzheimer’s symptoms in 9 out of 10 people.
- Animal studies also suggest that fasting may protect against other neurodegenerative diseases, including Parkinson’s disease and Huntington’s disease.
However, more studies in humans are needed.
10. It could extend your life
- One of the most exciting benefits of intermittent fasting may be its ability to extend lifespan.
- Studies in rodents have shown that intermittent fasting extends life similarly to continuous calorie restriction.
- Intermittent fasting has also been shown to increase the lifespan of fruit flies.
- In some of these studies, the effects were quite dramatic. In an earlier study, rats fasted every other day lived 83 percent longer than rats not fasted.
- In a 2017 study, mice fasted every other day increased their lifespan by about 13 percent.
- Daily fasting was also shown to improve the general health of male mice. It helped delay the onset of conditions like fatty liver disease and hepatocellular carcinoma, which are common in aging mice.
- Although this is far from being determined in humans, intermittent fasting has become very popular among people fighting aging.
- Considering the known benefits for metabolism and all sorts of health markers, it makes sense that intermittent fasting could help you live a longer, healthier life.
- Intermittent fasting is a very popular method of losing weight, but its benefits go beyond that. It may also help you live a longer, healthier life, according to studies involving animals and humans.
- There are many different forms of intermittent fasting. Some methods include fasting for certain hours of the day. Other methods only require you to fast on certain days of the week. Approaches, and results, vary.
- If you’re interested in starting intermittent fasting, consider talking to your doctor or a nutrition expert today. They can help you determine if it is safe for you.