Obesity, for example, is one of the 10 most common causes of death in the world. It has a major impact on healthcare costs, life expectancy, and quality of life. No wonder people want to find ways to reverse and prevent disease. Fasting has been practiced for thousands of years in many cultures and religions around the world. Only recently have scientists been able elucidate its many health benefits.
Fasting has been practiced for thousands of years in many cultures and religions around the world. Only recently have scientists been able elucidate its many health benefits.
Fasting types
Fasting can range from eight hours up to seven days.
- Intermittent fasting (IF)This type alternates healthy eating days and fasting days. Fasting days can range anywhere from 0 calories to 600 calories. There are three common methods:
- Periodic fasting: Regimens vary from 16 hours to 5-7 consecutive days. Water-only fasting or reduced calorie days are possible.
Health benefits
Intermittent fasting has many benefits, including:
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- Weight loss increases. Global obesity, estimated to affect 300,000,000 people by 2025, will be a worldwide epidemic. The average weight loss from intermittent fasting is 3 to 7 percent, and this includes the alternate-day method. Multiple studies reviewed found greater visceral fat loss when IF was compared to daily calorie restriction. The majority of existing studies have a short duration. Therefore, larger and longer studies are required.
- Improves metabolism. Intermittent fasting has shown improvement in cardiometabolic variables like A1c and blood sugar. Animal studies have shown that IF improves heart rate, blood flow, and heart rate variation. It is possible that IF can improve long-term heart health.
- Dr. Dr. Valter Longo is a researcher on longevity and fasting. He reports that fasting promotes stem-cell regrowth, metabolic health and adaptive cellular responses. It also stimulates autophagy and DNA repair. Autophagy, the body’s “detoxification” process, is responsible for cleaning up and eliminating damaged cellular tissues and debris. These cellular changes affect longevity, quality of life and healthspan.
- Stress response and inflammation are improved. In a small study, overweight participants with asthma showed improved markers of inflammation and oxidative stress as well as asthma-related symptoms and quality of living within two weeks of a 8-week alternate day fasting regimen. In an animal study, IF reduced inflammatory pathways and preserved brain health.
- Contributes to cancer preventive measures. Researchers and patients are still trying to determine the causes of cancer, which is the second most common cause of death in the world. Fasting for at least 2 days has been shown to be as effective as chemotherapy in slowing the progression of various cancers and protecting healthy cells. Research has shown that fasting can also reduce tumor growth in mice.
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Risks
Healthcare professionals don’t recommend fasting for people with malnutrition or eating disorders because it involves significant calorie restrictions or avoiding all food. Wait to fast if you are acutely sick until you feel better. Talk to your doctor if you are taking medication.
Intermittent fasting is generally considered safe by most people. However, it has few side effects. Be prepared to experience hunger or fatigue as your body adjusts. If you are feeling unwell, discontinue your fast.
Fasting Tracker
You may find a number of metrics helpful while fasting. Many of these can be done at home using readily available tools such as fitness trackers, blood meters and apps.
Regularly check blood glucose, blood ketone levels, and heart rate. Fasting Apps such as Simple or zero can also help identify your eating and fasting patterns over time.
Bottom Line: Is IF Right for You?
Intermittent and short-term rapid-calorie-reduction fasting is a powerful tool for many people to prevent and reverse lifestyle-related diseases. Consult your doctor or dietitian for help in developing the diet and fasting approach that is right for you.
Resources
- NIH. Age and Energy Intake Interact to Modify Cell Stress Pathways and Stroke Outcome.
- NIH. Impact of intermittent fasting on health and disease processes.
- NIH. The epidemic of obesity.
- DietDoctor. Longer fasting regimens – 24 hours or more.
- NIH. Alternate day calorie restriction improves clinical findings and reduces markers of oxidative stress and inflammation in overweight adults with moderate asthma.
