Beneficial effects of intermittent fasting


Greetings to all! There are many benefits to intermittent fasting. You can improve your mood, become smarter and more motivated. Even your meal will be tastier. Does it sound like an apple sauce? Yes, it does but there is a smaller number of side effects.

While you are eating, let’s begin with simpler effects. Then, to avoid too complicated scientific sentences, we’ll tell you about more difficult events.

Weight loss

I don’t want to overfocus on several fictions (e.g., ”Despite fasting, I don’t thin down at all”) because, although it may sound quite cynical, there were no fat men and women in the Buchenwald and Oswiecim. Indeed, there is a link between overweight and prolactin/estradiol level. Increased levels of these hormones lead to more ”watery” body (1). Low levels of thyroid hormones T3 and T4 result in slower metabolism (2). In general, fasting induces weight loss. Its speed is not the issue.

Well, assume that you don’t care about your appearance. Why should you thin down? So, look at these two facts. Overweight reduces lifetime (34) and we’d like to reach old age instead. Overweight increases risks of various diseases such as ischemic heart disease, depression, impotence and cancer (5). Thus, you may live long but not very well.

Tastier food

Do you want to feel yourself happy while eating a piece of bread? Just fast for couple of days!

Each food intake induces release of dopamine, serotonin, cannabinoids and opioids. These molecules boost your mood (6). Moreover, there is a link with insulin, ghrelin and leptin. These molecules support saturation and transport of proteins/lipids/carbohydrates.

What’s the point? Why will your food become tastier?

Food intake induces a burst of ”joy molecules”. Frequent multiple intakes of tasty food result in more frequent bursts. Repeated releases of, for example, dopamine and serotonin lead to decreased sensitivity of their receptors. Finally, generous food gives less pleasure. That’s all!

Naturally, a neurotransmitter release is not comparable with effect of a narcotic excitor. However, we eat for several times every day and some people do it even at nights. In this case, addiction is related to the time of food intake.

In brief, let’s talk about insulin: plenty of food – plenty of insulin – adipopexis – plenty of leptin – leptin inhibits receptor sensitivity to insulin – high sugar level in blood – death of pancreatic beta-cells – diabetes. So, let’s generalize the second practical aspect of short-term fasting. The more sensitive receptors are, the tastier food is.


Growth hormone has several fractions in a human body (e.g., bone growth, wound/trauma healing, nerve cell growth etc.). In brief, it supports growth of almost all the structures (unfortunately, even cancerous cells). However, we’ll talk about this later.

First of all, ghrelin is an appetite hormone. The higher its level is, the hungrier you are.

Thus, high level of ghrelin or low level of insulin increases growth hormone value (78). But how much?

The value varies from 200% to 1000% for 1-2 fasting days (910). To put it in crude terms, a daily generous food intake increases release of growth hormone by 2-3 times higher permanently. However, it does not mean equal speed of a fracture/abrasion healing. Since you can receive less vitamins, microelements or even proteins, recovery will be conditionally the same. The total balance accelerates regeneration for sure.

Fasting can be suitable to recover the brain of a drug addict.

Fasting and cancer

We ignored the fact that short-term fasting can change not only growth hormone level but also many other parameters of a human body. In total, these changes are more likely to reduce risk of cancer. This like 1 step backward and 2 steps forward. Indeed, fasting itself or chemotherapy + fasting accelerate death of cancerous cells (11 , 12 , 13 , 14 ). Since it’s impossible to foresee all, even a person adherent to a healthy diet can die from cancer. Everyone dies. However, the diet may prolong his/her lifetime. You may hear some tales about a 100-year-old person who smoked and drank alcohol every day. The point is that we don’t know when he/she would die without these addictions. On the one hand, the person may live 120 years. On the other hand, alcohol and tobacco enabled social activity and absence of depression. That’s why, their withdrawal may reduce his/her lifetime to 80 years. It doesn’t happen very often.

Fasting and intellect

According to the mouse study, intermittent fasting resulted in improved memory during a labyrinth testing and thicker layer of pyramidal neurons in hippocampus. Hippocampus is a center of short-term memory that helps you to  memorize a phone number or anyone’s appearance for a while. Even dendritic net is enlarged. What does it mean? To put it in crude terms, this is a little muscle-like cerebral pumping (15). Your brain become more active, and dementia risk is reduced (16 , 17).

Also, proliferation or reproduction or neurogenesis of hippocampus cells is mentioned. In 3 months, the group of mice demonstrated 30% larger ”random access memory” of the brain. It is not bad, is it (18)?

More than likely, growth of our precious BDNF (i.e., a protein that protects your nerves and provides construction of new nerve connections) level is one of intellect enhancement methods. In particular, it accelerates learning. Also, it increases growth by 50% (19).

But what about people?

Intermittent fasting is harmful for a malnourished (underweight) child but it has a beneficial effect on normal weight and overweight children (20). 48-hour fasting induces growth of aggression and intellectual abilities in adults (21).

Finally, meta-analysis of 3 studies leant toward greater beneficial effect of moderate fasting (22).

There are also several profits for seniors with normal weight and overweight. Thus, 3-month 30% lower consumption of kcal led to 30% increase in results of memory testing (23). In general, moderate fasting and weight loss increase mental capacity (except for underweight persons).

The best ”fasting”

Since balance is the base for all the things, it is no question that you won’t become Einstein if you eat once a week. That’s why, we need regular frequent fasting periods. Intermittent fasting is suitable for the purpose. In particular, you should eat for 8 hours a day. Then, you should consume nothing but water.

The diet enables both weight gain and easier weight loss. In fact, we get all our daily diet in 8 hours. Thus, although daily caloric value is the same, increased levels of ghrelin and growth hormone, as well as recovery time related to receptors to dopamine, insulin and serotonin are maintained longer.

However, I don’t always follow the rule because my food intake is lower than normal value. Moreover, I thin down immediately.

The second common schedule is as follows: follow your normal diet for 5 days a week but eat 500-600 kcal/day for 2 days. Actually, this is a single food intake daily.

So, everyone can choose to his/her taste.


  • Arrange fasting periods sometimes but avoid extreme diets (e.g., only water consumed for 7 days etc.).
  • Try going to bed when you are little hungry. Do not eat immediately after waking up. Drink a glass of lukewarm water and eat 30-60 minutes thereafter.
  • Mild fasting has several benefits: improves intellect, well-being and cell regeneration as well as restores receptors sensitivity.