An overview of the various types of fasting, from diagnostic to religious.
Diagnostic fasting falls in the category of medical fasting, however, the reason for fasting is not geared towards health benefits, but rather towards determining the cause behind a person’s (usually a child’s) low blood pressure. This method is used when low blood sugar levels are causing other health problems that need to be investigated. This fasting method is helpful because it can indicate whether the problems are caused by an endocrine or a metabolic problem. The endocrine is the system of glands and organs that make hormones and release them directly into the blood so they can travel to tissues and organs all over the body.
During this type of test, you are only allowed to drink water. Every hour, a sample of blood will be taken and the blood sugar levels will be monitored. The process is continued until the blood sugar levels drop to an acceptably low level, or for a set period (determined by the doctor).
Fasting for a Blood Test
Similar to diagnostic fasting, this type of fasting is also in the category of medical fasting. Though this is not necessarily blood sugar related, as with diagnostic fasting, it still involves fasting (usually between 8-12 hours) to succeed in a certain blood test. In this type of fast, you usually should abstain from food and fluids (except water) for the given period to have an accurate test result. The vitamins, minerals, fats, carbohydrates, and proteins that make up all food and beverages can impact blood-level readings, clouding the results of your test.
Cases, where this type of fasting is necessary for blood testing, include Diabetes tests, tests to check your cholesterol levels, tests for liver and kidney functioning, vitamin B-12 testing, Iron test, triglyceride level test, basic metabolic panel, renal function panel, lipoprotein panel, and Gamma-glutamyltranferase. Though this summarizes the main tests where this type of fasting is necessary, there could be other cases where your doctor will require you to fast for accurate blood test results.
Fasting for Religion
Fasting for religious reasons is not new to this day and age. Fasting is, and has been, an essential part of many religions, including Christianity, Islam, and Buddhism.
Christians fast as a means to grow in their relationship with God. Christian fasts can vary in length, and it typically involves abstaining from food for a set time period, or abstaining from certain types of food. For example, the biblical Daniel Fast, which prohibits the consumption of animal products, refined carbohydrates, food additives, preservatives, sweeteners, flavorings, caffeine, and alcohol.
Islamic Ramadan, the Muslim holy month of fasting, is a 28-30 day fast where you are not allowed to eat or drink during day time, or smoke and engage in sexual activity for the duration of the fast. This tradition goes back several millennia. The day starts with a pre-dawn meal called Suhoor and is broken at dusk with a meal called Iftar (often in the form of a feast with family and friends).
Dry fasting is also known as absolute fasting. While water fasts allows the intake of water (and sometimes even certain teas), a dry fast restricts both food and liquid intake. This fast doesn’t allow any liquid intake, including water, broth, and tea. This is very different from most fasts, which encourages water intake.
There are many ways to dry fast. Dry fasting is mostly done in conjunction with intermittent fasting options. This means that during your ‘off’ window (fasting window) you will neither consume any foods nor drink any liquids.
Though fasting is associated with many health benefits, dry fasting, especially for a prolonged time, could be very dangerous. You can run the risk of dehydration and other complications. This is especially risky if you are dry fasting and working out simultaneously, because your chances for dehydration is increased when you exercise.
A water fast is also known as the zero-calorie diet and is one of the most intense forms of fasting. As the name implies, during a water fast you can only drink water while consuming zero calories. This fast is mainly used as a way to detoxify your body. Though other fasting methods also have a detoxifying effect to some extent, according to experts, a water fast is the fastest way to rid your body of unwanted toxins. Just like with many other fasts, the length of this fast can vary, from 1 day to over a month.
One obvious benefit of a water fast is rapid weight loss. The amount of weight loss will be dependent on the length of your fast. However, there is a point where your body reaches a ‘fasting plateau’, so fasting for extended periods will not necessarily guarantee more weight loss.
The most important thing during this fast is to stay hydrated (9-13 glasses of water daily).