Are there any health benefits to fasting?

When we hear the word ‘fast’ in conjunction with diet, we may think of food fads such as juice diets and the 5:2 plan. However, fasting has long been a part of life for the religious among us. Jews fast for Paryushan-the eight-day festival honouring the soul, Muslims fast for the month of Ramadan and orthodox Christians fast for Lent. With Lent beginning today, many people – religious or not – will be choosing to fast whether it be to show respect for our God or simply to test our own willpower. However, before you begin your fasting it is important to understand how fasting works and how it effects your health.


What is fasting?

Fasting is not simply the abstention from all foods. Fasting is defined as “an abstinence from food, or a limiting of one’s food, especially when voluntary and as a religious observance”.

The three most common types of fast are:

Calorie Restriction: the reduction of kilocalorie intake by 20-40%. i.e fasting diets.

Alternate Day Fasting: Alternate day periods, such as one day of ‘feast’ and one eve of ‘fast’. i.e. Ramadan fasting.

Dietary Restriction: The elimination or reduction of one or more components from your diet. i.e giving up bread for Lent.


Is it good for my health?

These three popular fasting methods are all different, so there is no blanket answer as to how fasting can effect your health. Here we have looked in depth at the health effects of the three types of fast mentioned above.

Calorie Restriction: This type of fasting has been demonstrated to improve health and increase long life in a whole variety of species, both human and non-human. It also delays the onset of many diseases, including cancer, diabetes, respiratory diseases, renal and neurodegenerative diseases. Calorie restriction fasting can also impact your heart health, decreasing resting heart rate and blood pressure, while improving heart function.

Alternate Day Fasting: This religious fast of alternating day periods has been shown to have many great health effects, including extended lifespan, prevention of kidney disease, cardiovascular disease and cancers, and decreased heart rate and blood pressure. However, women partaking in this type of fast can become intolerant to glucose.

Dietary Restriction: Unlike calorie restriction and alternate day fasting, dietary restriction has not shown any increase in life span when tested with carbohydrates and lipids. However, the restriction of protein can increase lifespan by 20%. Yet, this has been tested in animals and has yet to be tested with human subjects.


How can I fast safely?

To ensure that you remain healthy whilst fasting, you must ensure that what you are eating is beneficial to your body. Remember that no matter how little you are consuming, you must still take in the major food groups- fruit and vegetables, carbohydrates, protein, diary and good fats. Try to fill up on the complex carbohydrates rather than sugary, processed foods, as while the latter will give you a burst of energy and leave you deflated, the carbohydrates will provide slow release energy throughout the day.

Fasting has many health benefits, if done properly. You can reduce cravings, detox your body and stave off diseases. If you are going to be fasting for lent, then remember to be aware of what you are putting in your body. If you are lacking any nutrients then consider taking supplements to give your body what it needs, and finally, make sure that you are getting enough rest throughout this fasting period! Happy fasting!