Intermittent fasting is a way of eating where you cycle between periods of eating and fasting.
There are several different ways of intermittent fasting, such as the 16/8 or 5:2 methods.
Various studies show that it can have tremendous benefits for your body and brain.
10 evidence-based health benefits of intermittent fasting are the following:
1. Intermittent Fasting Changes The Function of Cells, Genes and Hormones
When you don’t eat for a while, many things happen in your body.
For example, your body begins essential cellular repair processes and adjusts hormone levels to make stored body fat more attainable.
Following are some of the changes that occur in your body during fasting:
- Insulin levels: Blood levels of insulin drop remarkably, which promotes fat burning (1).
- Human growth hormone: The blood levels of growth hormone may increase as much as 5-times (2, 3). Higher levels of this hormone promotes fat burning and muscle gain, and have several other benefits (4, 5).
- Cellular repair: The body begins important cellular repair processes, such as removing waste material from cells (6).
- Gene expression: There are beneficial changes in many genes and molecules associated with longevity and protection against disease (7, 8).
Lots of the benefits of intermittent fasting are associated with these changes in hormones, gene expression and function of cells.
2. Intermittent Fasting Can Help You Lose Weight and Belly Fat
Simply speaking, intermittent fasting will make you consume fewer calories.
Many of those who try intermittent fasting are practicing it for the purpose of weight loss (9).
Unless if you compensate by eating in bulk in your eating window, you will end up taking in fewer calories.
Additionally, intermittent fasting improves hormone function to promote weight loss.
Reduced insulin levels, higher growth hormone levels and increased amounts of norepinephrine (noradrenaline) all enhance the breakdown of body fat and promote its use for energy.
In other words, intermittent fasting works on both sides of the calorie equation. It improves your metabolic rate (increases calorie burn) and lowers the amount of food you eat (reduces calorie intake).
According to a 2014 review of the scientific literature, intermittent fasting can lead to weight loss of 3-8% over 3-24 weeks (12). This is a large amount.
The people also lost 4-7% of their waist circumference, which indicates that they lost much more of belly fat, the harmful fat in the abdominal cavity that leads to disease.
One review study also showed that intermittent fasting caused less muscle loss than continuous lowering of calorie. (13).
All things considered, intermittent fasting can be an unbelievably powerful weight loss tool. More details here: How Intermittent Fasting Can Help You Lose Weight.
3. Intermittent Fasting Can Reduce Insulin Resistance, Lowering Your Risk of Type 2 Diabetes
Type 2 diabetes has become very common in recent decades.
Its main feature is increased blood sugar levels in the context of insulin resistance.
Anything that lowers insulin resistance should help decrease blood sugar levels and prevent type 2 diabetes.
Interestingly, intermittent fasting has been shown to have major benefits for insulin resistance and cause a noticeable lowering in blood sugar levels (12).
In human studies on intermittent fasting, fasting blood sugar level has been decreased by 3-6%, while fasting insulin has been decreased by 20-31% (12).
One study in diabetic rats also revealed that intermittent fasting prevents kidney damage, one of the most severe complications of diabetes (13).
What this suggested, is that intermittent fasting may be very protective for people who have risk of developing type 2 diabetes.
4. Intermittent Fasting Can Reduce Oxidative Stress and Inflammation in The Body
It involves reactive molecules known as free radicals, which react with other important molecules (like protein and DNA) and damage them (15).
Oxidative stress is one of the steps towards aging and lots of chronic diseases (14).
5. Intermittent Fasting May be Beneficial For Heart Health
Heart disease is now a days the world’s largest killer (20).
It is known that various health markers (so-called “risk factors”) are related to either an increased or lowered risk of heart disease.
Intermittent fasting has been shown to improve several different risk factors, including blood pressure, total and LDL cholesterol, blood triglycerides, inflammatory markers and blood glucose levels (12, 21, 22, 23).
However, many of these studies are performed on animals. The effects on heart health need to be studied in detail further in humans before suggestions can be made.
6. Intermittent Fasting Induces Various Cellular Repair Processes
This includes the cells breaking down and metabolizing broken and dysfunctional proteins that build up inside cells over time.
7. Intermittent Fasting May Help Prevent Cancer
Cancer is a threatening disease, characterized by uncontrolled growth of cells.
Fasting has been shown to have lots of beneficial effects on metabolism that may cause lower risk of cancer.
There is also some evidence on human cancer patients, revealing that fasting lowered various side effects of chemotherapy (31).
8. Intermittent Fasting is Good For Your Brain
What is good for the body is usually good for the brain as well.
Intermittent fasting boosts various metabolic functions known to be important for brain health.
This includes lowered oxidative stress, decreased inflammation and a lowering of blood sugar levels and insulin resistance.
It also elevates levels of a brain hormone called brain-derived neurotrophic factor (BDNF) (32, 34, 35), reduction of which has been implicated in depression and several other brain complications (36).
Animal studies have also shown that intermittent fasting protects against brain damage because of strokes (37).
9. Intermittent Fasting May Help Prevent Alzheimer’s Disease
Alzheimer’s disease is the most common neurodegenerative disease of the world.
Alzheimer’s disease can’t be cured , so preventing it from showing up in the first place is critical.
A study in rats shows that intermittent fasting may retard the onset of Alzheimer’s disease or lower its severity (38).
In a lots of case reports, a lifestyle involvements that included daily short-term fasts was able to noticeably improve Alzheimer’s symptoms in 9 out of 10 patients (39).
10. Intermittent Fasting May Extend Your Lifespan, Helping You Live Longer
One of the most interesting applications of intermittent fasting may be its ability to increase lifespan.
In some of these studies, the effects were totally unbelievabe. In one of them, rats that fasted every other day lived 83% longer than rats who weren’t fasted (44).
However, this is far from being proven in humans, intermittent fasting has become very common among the anti-aging groups.
Given the known benefits for metabolism and all types of health markers, it makes sense that intermittent fasting leads to longer and healthier life.
You can find more information about intermittent fasting on this page: Intermittent Fasting 101 – The Ultimate Beginner’s Guide.