How does fasting affect my body?

Nov 18, 2020

woman doing yoga during sunset

Fasting has recently become incredibly trendy as a tactic for weight loss. However, it is not something new. For decades people have been engaging in fasting and Intermittent Fasting (IF) for health and spiritual reasons. Many successful people also engage in fasting to gain improved focus and mental productivity. But, how does fasting actually work? Is it as good as people say? Should I try it?

In our article “Fasting 101” our Hudson Dietitian explains what fasting is, and gives you a recommendation regarding introducing it to your life. Today, we are explaining how fasting affects our body with the emphasis on its benefits and risks, so you can make a well-informed decision.

What happens inside my body?

Harvard Health Publishing explains that the food we eat gets broken down by the enzymes in our guts and ends up as molecules in our bloodstream ready to be used. Carbohydrates are quickly broken down into sugar, which our cells use for fat – the excess sugar is stored as fat. Insulin, a hormone produced in the pancreas, is released as we consume food to allow the body to use, or store the blood sugar. As the insulin levels drop between meals, the fat cells can be broken down for energy. In order to save energy, the body also removes many other redundant, or damaged components like immune cells, or hormones, and toxins.

The benefits of fasting

Fasting and IF hold the promise of providing incredible benefits to different aspects of your life and body. These include the benefits of weight loss, health improvement, and spiritual development. Below we explain each in detail.

Weight loss

It is believed that around 8 hours after consuming a meal the body enters the state of ketosis – burning fat cells for energy. A study shows that during ketogenesis there is a low stimulus for insulin secretion, which results in a reduction in fat and glucose storage. Furthermore, other hormonal changes contribute an increased breakdown of fats. This has been proven to be “very effective for rapid weight loss”. Therefore, a combination of IF, or fasting, with an active lifestyle and a healthy diet will surely result in sustainable weight loss in Hudson.


Fasting and IF hold the promise of improving heart health, diabetes, brain function, the immune system, among many others.

Heart disease is considered to be the leading cause of death worldwide – in 2017 31.5% deaths occurred due to heart disease. IF and fasting has been proven to reduce LDL (bad) cholesterol levels, total cholesterol levels and decrease blood pressure, all of which contribute to better heart health.

Type 2 diabetes is improved with fasting as it reduces insulin resistance. During fasting there is little insulin secretion (if any), therefore with regular IF the body’s insulin sensitivity increases making glucose transportation more efficient. Furthermore, as the body has to use up its stores of sugar between meals, the overall blood sugar levels reduce, preventing spikes and crashes.

The improved brain function and the immune system as a result of fasting go hand-in-hand. As a study states “Stimulation of the peripheral immune system is known to bring along changes in brain function and behavior.” The research on this topic has been mostly conducted on animals, hence the effects on humans require more attention.
Another study published by Cell Stem Cell explains that fasting for extended periods of time forces your body to save energy, which is partially done by recycling the redundant and damaged cells, especially immune cells. The removal of redundant components of our bodies and production of new ones leads to the reduction of the growth hormone IGF-1 that’s linked to cancer, aging and tumor growth, as well as a reduction in the risk of developing Alzheimer’s, and Parkinson’s disease.


Spiritual fasting is emphasized in many religions, including Judaism, Christianity and Islam. It involves abstaining from food while focusing on prayer – it can mean refraining from snacks, skipping meals, or not eating for an entire day. People believe that it provides unique spiritual benefits to the life of the believer as it requires self-control and discipline to deny yourself the natural desires of the body. As the focus is taken away from physical things, the believer can gain spiritual clarity of thought.

Apart from religion, spiritual fasting can be practiced to promote the connection of our body to our minds and spirit. People often practice spiritual fasting during times of struggle, to overcome a test of faith, or to reconnect with nature.

The risks of fasting

Fasting, like any other diet, requires utmost care and guidance when being carried out as wrongly engaging in it can cause more damage than benefits. Our dietitian believes that starvation diets are not the best for losing weight as in the longer run they can reduce your metabolism. This means that once you start eating again, your body will not be as efficient at processing it, causing the excess sugars and fats to be stored.

Furthermore, an important pitfall of fasting for weight loss is that it is immensely demanding in terms of self-control and discipline. Therefore, many people find that this diet is not sustainable and, in fact, doesn’t support long term weight loss. Another Harvard Health Publishing states that after you are deprived of food your appetite hormones and the hunger center in the brain go into overdrive – this is a strong biological push to overeat following fasting.

In general, it is recommended for anyone interested in starting a fasting diet to consult a doctor, or a dietitian to ensure safety. Calorie restriction is particularly dangerous for people with diabetes, anaemia, people taking medications for heart conditions, and pregnant women. Whether fasting, or IF are safe for you to try depends on your specific medical needs, lifestyle and current physical and mental state.

Find out more about our Hudson Dietitian

Our highly qualified weight loss experts at Batista Weight loss and Wellness: Susan West-Opyoke, RDLD; John Batista, M.D.; Stephanie, M.A; and Valerie, Office Staff, together have decades of experience working with weight loss patients.

At Batista Weight loss and Wellness we believe that successful weight loss depends on two factors – the knowledge about how to lose weight and following through on your weight loss plan. Our experts will provide you with a customized weight loss plan, and regular face-to-face interaction and motivation.

To create your own customized weight loss plan with us and achieve sustainable weight loss in Hudson don’t hesitate to contact us on (352) 600-3476 or drop us a visit at our clinic: 443 Mariner Blvd, Spring Hill, FL 34609, USA.

The material contained on this site is for informational purposes only and DOES NOT CONSTITUTE THE PROVIDING OF MEDICAL ADVICE, and is not intended to be a substitute for independent professional medical judgment, advice, diagnosis, or treatment.  Always seek the advice of your physician or other qualified healthcare provider with any questions or concerns you may have regarding your health.