The Science of Fasting: Proven Health Benefits Backed by Research

The holiest day in Judaism is Yom Kippur. On this day there are five prohibitions, one of which is the prohibition against eating and drinking. In recent years, people have begun using the fast as a method of detoxifying the body — an idea that is actually not new at all.

Maimonides (the Rambam) used fasting as a treatment for illness. In his book Pirkei Moshe he wrote: “I know that many patients who suffered from certain illnesses and had strong bodies and great physical power, I healed them by refraining from food for a long time and administering remedies during that period. Others who suffered from well-known diseases, whose strength was lacking and who were weak, I healed by preventing them from eating until their strength returned. Their strength returned to them, and they recovered completely.”

Dr. Herbert Shelton likewise believed strongly in healing through fasting, and even wrote a book titled Fasting Can Save Your Life.

According to natural medicine, illness occurs when the body cannot clear toxins and waste at the rate at which they accumulate. During a fast, the organs of the body receive a period of “rest” that allows for recovery and renewal. When the body no longer uses most of its energy for digestion and waste removal, it can redirect that energy toward eliminating toxins that have built up over many years.

Conventional medicine also recognizes the therapeutic benefits of structured fasting. Medical studies in recent years have demonstrated significant health advantages. Following are some of the key findings:

Helps regulate blood sugar levels

Naturopath Efrat Navon explains: “Studies show that fasting increases insulin sensitivity. Insulin becomes more efficient at transporting glucose into the cells, meaning the body responds better to carbohydrates and sugar.”

Supports weight loss

“During fasting, there is an increase in the levels of norepinephrine — a neurotransmitter that increases metabolic rate. When we do not consume carbohydrates, the body begins using fat as its energy source, leading to a reduction in body fat percentage. At the same time, growth hormone levels increase during fasting, which further boosts metabolic rate.”

Slows aging processes

“Extensive research on fasting has shown a positive connection between restricted eating and increased lifespan. Studies have found that fasting accelerates cellular renewal and repair — processes that normally decline with age.”

Improves cognitive function

“Fasting increases production of a protein called BDNF, which stimulates brain activity essential for a healthy nervous system. It protects brain cells from degenerative diseases and promotes the growth of new neurons.”

Strengthens the immune system

“When the digestive system is working, the immune system rests — and vice versa. During fasting, when digestion rests, the immune system (about 70% of which resides in the gut) becomes more active, produces new white blood cells, and strengthens overall.”

It is important to note that therapeutic fasting refers specifically to fasting where only water is consumed and no food at all. There are many types of fasting — one popular form is a juice fast, in which one drinks only vegetable juices and small amounts of fruit juice. Of course, any type of medical or therapeutic fast must be done solely under proper medical supervision.

Disclaimer: The information in this article is not a professional medical opinion, recommendation, substitute for expert consultation, or medical advice of any kind.