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20 Intermittent Fasting Benefits + Who Shouldn’t Try It

Written by Joe Cohen, BS | Reviewed by Selfhacked Science Team | Last updated:

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Intermittent Fasting

Dieting can be a difficult and frustrating way to lose weight. Intermittent fasting is a simple and effective strategy for getting lean while maintaining muscle mass.

What is Intermittent Fasting?

Intermittent fasting is a technique primarily used for losing weight that comes with many health benefits. It involves changing your eating pattern without having to change your diet or exercise level.

There are many different ways to fast. Common practices include:

  • Alternate day eating – one day on and one day off
  • Time restricted eating – typically involves skipping breakfast (but I don’t approve)
  • 5:2 fasting protocol – restrict calories to 500-700 per day for two days a week

Intermittent fasting is effective because it allows the body to enter its highest fat-burning state, which occurs about 8-12 hours after eating a meal. This helps eliminate body fat without sacrificing muscle mass. A typical eating schedule does not normally allow the body to reach this point.

1) Helps You Lose Weight

Studies have found that the 5:2 fasting protocol has been the most effective for losing weight [1].

A 2013 study found that people who steadily reduced their daily calorie intake became more insulin sensitive and lost more weight compared to people who followed a regular eating pattern [1].

Intermittent fasting has been effective in preventing obesity [2].

Metabolism efficiency is improved as a result of intermittent fasting [3].

2) Can Prolong Your Life

Intermittent fasting can increase a person’s lifespan by up to 30% according to some researchers (if animal studies are an indicator) [4].

Intermittent fasting boosts the body’s stress resistance, which increases longevity in humans [5].

It helps protect and treat the body from disease, which can delay aging [5].

Intermittent fasting can prolong the health-span of the nervous system by impacting biological pathways that regulate the lifespan [6].

3) May Reduce the Likelihood of You Getting Sick

In a study done on mice that were infected with salmonella, intermittent fasting lowered intestinal and systemic bacteria by boosting their intestinal immune system [7].

4) Promotes Cardiovascular Health

Intermittent fasting:

  • Decreases cardiovascular disease risk [8].
  • Increases HDL cholesterol and lowers triglyceride levels and LDL cholesterol [8].
  • Decreases resting heart rate and blood pressure [4].
  • Improves circulation of triglycerides and cholesterol [3].
  • Increases resistance to ischemic injuries [3].
  • Reduces the risk of coronary heart disease [9].

5) Decreases Cancer Risk

Intermittent fasting lowers blood glucose and IGF-1 levels, which reduces the risk of cancer [8].

Studies have found that reducing energy intake and fasting for longer intervals during the night can reduce the risk of breast cancer [10].

6) Can Forestall Cognitive Decline

Intermittent fasting protects neurons from genetic and environmental stress factors during aging [11].

Intermittent fasting increases insulin sensitivity, which benefits neurons that stimulate the production of enzymes that help cells cope with stress and fight against disease [11].

Fasting can reduce issues with brain function and neurodegenerative disorders caused by inflammation [10].

7) Can Prevent Chronic Degenerative Diseases

Fasting reduces inflammation and boosts cellular protection [5].

Intermittent fasting helps protect against obesity, diabetes, rheumatoid arthritis, hypertension, and asthma in humans [5].

Intermittent fasting protects against damage caused by an ischemic stroke [12].

Calorie restriction increase sirtuins and AMPK signaling, which help the body maintain internal stability [13].

8) Heals Your Gut

Motilin and Ghrelin, which regulate the digestive tract, are released during fasting [14].

Ghrelin readies the body for the incoming nutrients by stimulating gastrointestinal motility and gastric acid secretions [15].

Studies show that there may be a therapeutic use for ghrelin in gastrointestinal inflammatory diseases like colitis and ischemia (R).

Fasting therapy has improved abdominal pain, diarrhea, nausea, and anxiety in patients with irritable bowel syndrome [16].

9) Boosts Mood and Motivation

Studies show that fasting and calorie restriction improves anger, tension, confusion, and overall mood in aging males [17].

High levels of ghrelin are associated with anti-depressant effects [17].

10) Is A Cognitive Enhancer

IF affect energy and oxygen radical metabolism, and cellular stress response systems, in ways that protect neurons against genetic and environmental factors to which they would otherwise succumb during aging [11].

Fasting increases the presence of drebrin, a protein that regulates neuronal development [11].

The loss of drebrin results in cognitive impairment that causes neurological disorders [11].

Intermittent fasting is associated with hippocampus growth, which is responsible for emotion and memory [11].

11) Reduces Inflammation

Fasting produces ghrelin in the body, which suppresses inflammation [18].

Intermittent fasting reduces pro-inflammatory cytokines and immune cells in the body [3].

Fasting for long intervals at night can reduce systemic inflammation [10].

Intermittent fasting reduces the risk of degenerative diseases connected to inflammatory responses in the central nervous system [10].

12) Increased Ghrelin Levels May Slow the Onset of Parkinson’s Disease

Ghrelin increases the concentration of dopamine in an area of the brain where the decline of dopamine cells leads to Parkinson’s Disease [6].

13) Improves Learning and Memory

A study demonstrated that mice on intermittent fasting had better learning and memory than mice with a regular eating schedule [19].

Studies suggest that learning may be best when the stomach is empty during the day because ghrelin levels are high [19].

14) Protects Against Autoimmune Disease

Fasting every three days has been effective in reducing autoimmunity and promoting regeneration [20].

Studies have shown that periods of fasting reversed symptoms of multiple sclerosis in animals [20].

Fasting prevents and improves systemic lupus erythematosus [21].

15) Improves Sleep

Periods of fasting can lead to decreases in arousal during sleep [6].

Intermittent fasting has proven to benefit daytime performance and quality of sleep in non-obese individuals [6].

16) Helps Protect Against Infections

Periods of food deprivation increases resistance to Salmonella typhimurium infection because the body produces more IgA, which is critical in immune function [7].

Intermittent fasting promotes responses in the brain that suppress inflammation and maintain cognitive function during systemic bacterial infection [22].

Neutrophils have a preference to engulf refined carbohydrate (glucose, fructose, sucrose, honey, and orange juice) over bacteria [23].

The neutrophil phagocytic capacity to engulf bacteria is affected when simple sugars are digested. And fasting strengthens the neutrophils phagocytic capacity to engulf bacteria [23].

However, the digestion of normal starches has no effect. The researchers concluded that the scientific data found that the function, and not the number of phagocytes in engulfing bacteria was altered by the ingestion of sugars [23].

Even among sugars, neutrophils can again be picky and engulf preferred sugars [23, 24, 25].

17) Allows You to Maintain Your Performance

Intermittent fasting has no effect on daily functioning and sports performance [26].

Intermittent fasting does not promote drowsiness or lack of vigilance [27].

This method of fasting preserves lean body mass [28].

The cellular effects of intermittent fasting are similar to the effects of physical exercise [29].

18) Heals Your Skin

There is evidence that intermittent fasting may aid in skin wound healing [30].

Fasting has been effective in alleviating contact dermatitis and chronic urticaria [31].

The effects of intermittent fasting can assist with fighting acne (R).

19) Helps Ease Chronic Pain

Intermittent fasting enhances neuroplasticity and learning in adults, which can aid in healing chronic pain [32].

Joe’s Recommended Intermittent Fasting Plan

For most readers of this blog, I will recommend doing a restricted eating window from 8 am to 6 pm – that means eating only from 8 am to 6 pm.

You can also do the 5:2 protocol while you’re at it, which means to do a 24 hour fast two days a week (separated by at least one day).

Eat your normal diet five days a week. Pick any two days of the week to restrict your intake of food to fewer than 700 calories.

You will get the best results if your “normal diet” is a healthful one, but you do not need to try to restrict calories on your non-fast days.

For people with inflammatory issues, I’d recommend the Lectin Avoidance Diet.

Potential Side Effects

In a study involving mice who didn’t have LDL receptors, intermittent fasting increased insulin resistance, and total and LDL cholesterol compared to mice following a normal eating pattern [33].

Fasting can lower thyroid hormones, and decrease dopamine and serotonin – at least while you’re fasting.

Who Shouldn’t Do Intermittent Fasting

  • People with circadian rhythm issues
  • People who have problems related to the limbic system
  • People who get hypoglycemic
  • People who are severely underweight
  • People who are trying to have a child
  • People with hypercholesterolemia.

About the Author

Joe Cohen, BS

Joe Cohen won the genetic lottery of bad genes. As a kid, he suffered from inflammation, brain fog, fatigue, digestive problems, anxiety, depression, and other issues that were poorly understood in both conventional and alternative medicine.Frustrated by the lack of good information and tools, Joe decided to embark on a journey of self-experimentation and self-learning to improve his health--something that has since become known as “biohacking”. With thousands of experiments and pubmed articles under his belt, Joe founded SelfHacked, the resource that was missing when he needed it. SelfHacked now gets millions of monthly readers.Joe is a thriving entrepreneur, author and speaker. He is the CEO of SelfHacked, SelfDecode and LabTestAnalyzer.His mission is to help people gain access to the most up-to-date, unbiased, and science-based ways to optimize their health.
Joe has been studying health sciences for 17 years and has read over 30,000 PubMed articles. He's given consultations to over 1000 people who have sought his health advice. After completing the pre-med requirements at university, he founded SelfHacked because he wanted to make a big impact in improving global health. He's written hundreds of science posts, multiple books on improving health, and speaks at various health conferences. He's keen on building a brain-trust of top scientists who will improve the level of accuracy of health content on the web. He's also founded SelfDecode and LabTestAnalyzer, popular genetic and lab software tools to improve health.

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