Fasting has been used for millennia worldwide by people from nearly every part of the globe for both spiritual and health reasons. In the last few years, fasting has gained popularity as a way to improve health and lose weight. But is there any scientific evidence to support the hype?
What is Fasting?
In short, fasting refers to the practice of depriving oneself of food and occasionally liquids for a certain amount of time. There are several different methods of fasting, depending on the individual and the desired outcome. Some methods of fasting include intermittent fasting and prolonged fasting.
Intermittent fasting is the most popular type of fasting and has gained steam in recent years, likely because of social media. This type of fasting involves cycling between periods of eating and periods of fasting. For example, an individual may choose to eat only between the hours of 12:00pm and 8:00pm. The fasting window in this example would be between 8:01pm and 11:59am the following morning. During the fasting window, the only thing consumed is water.
Periodic fasting is the practice of fasting for more extended periods of time - typically 24 to 72 hours. When done solely for health and wellness reasons, this is usually done once a week (in the case of 24 hour fasts) or once a month (for 72 hour fasts). While there is low risk of negative health impact from fasting for 24 hours for a person who is overall healthy, fasting can be dangerous when done for longer periods or when done by individuals with conditions such as type 2 diabetes.
The Benefits of Fasting
There are a number of benefits associated with fasting. Some of the benefits of fasting include weight loss, increased metabolism, and more energy. In addition, fasting has also been shown to reduce the risk of chronic diseases such as diabetes and heart disease, two of the biggest causes of death that plague the American healthcare system.
One of the most significant benefits of fasting is weight loss. Fasting has been shown to help people lose weight by reducing the number of calories consumed and by increasing metabolism. When fasting, the human body switches from burning carbohydrates for energy to instead burning fat. The result is that the body goes into a ketogenic state, which can result in a significant amount of excess fat loss.
A randomized control study published in the Nutrition Journal in 2022 compared intermittent fasting two days per week versus one day per week. The study followed 20 overweight men and women for 4 weeks. The researchers concluded that body composition, cardiovascular health, and hunger were all improved by intermittent fasting.
Improve Your Metabolism
Fasting has also been shown to improve metabolism, which is the process by which your body converts food into energy. When you fast, your body goes into a state of ketosis, which is when your body burns fat for energy instead of using carbohydrates such as glucose.
A controlled clinical trial published in Cell Metabolism studied the impact of intermittent fasting on men with prediabetes. The study found that intermittent fasting improved insulin sensitivity, which is the body's ability to use insulin to process carbohydrates. Intermittent fasting had positive effects on blood pressure, oxidative stress, and appetite.
Increase Your Energy Levels
Fasting can also help to increased energy levels. Part of why people get tired immediately after eating a large meal is how the body's insulin levels increase after a meal. However, when you fast, your body switches from burning glucose for energy to burning fat for energy. This change in the body's metabolism can result in increased energy levels. Fasting also stimulates the production of human growth hormone, which has been shown to improve energy levels and help muscle growth.
Prevent Chronic Diseases
In addition to helping with weight loss, fasting has also been shown to reduce the risk of chronic diseases such as diabetes and heart disease. A study published in Clinical Diabetes and Endocrinology in 2021 reviewed the scientific literature on the impact of intermittent fasting on type 2 diabetes. The study determined that "intermittent fasting is an effective non-medicinal treatment option for type 2 diabetes".
Intermittent fasting and periodic fasting have a remarkable potential for improving the health of millions of Americans. Individuals should always discuss practices like fasting with their personal physician. When done safely and under medical supervision, fasting may be a hidden gem to unlock the human body's healing potential.
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Sutton EF, Beyl R, Early KS, Cefalu WT, Ravussin E, Peterson CM. Early Time-Restricted Feeding Improves Insulin Sensitivity, Blood Pressure, and Oxidative Stress Even without Weight Loss in Men with Prediabetes. Cell Metab. 2018 Jun 5;27(6):1212-1221.e3. doi: 10.1016/j.cmet.2018.04.010. Epub 2018 May 10. PMID: 29754952; PMCID: PMC5990470.