Understanding Benefits and Application of Fasting

Fasting has been around for so many centuries. When you look at various religions, there always will be a fasting ritual. When you look at Muslim, there is Ramadan. Jewish has Yom Kippur where dry fasting last for 24 hours. Dry fasting means no water. Buddhist practice fasting for 18 hours everyday. Jesus and Moses fasted for 40 days. Simply, fasting is nothing more than a duration of time that you are not consuming calories.

Fasting has been catching attention of so many dieters and fitness enthusiasts. Mostly because of weight loss benefit, however, fasting has other amazing benefits. At the same time, there has been a lot of misunderstanding and myth regarding fasting to the point where people are scared of fasting or taking it too extreme that they are risking their health.

Physiological Benefit of Fasting

Biggest benefit of fasting is suppressing the insulin and able to utilize fat as energy source. When we eat, insulin level increases and forcing the body to store energy rather than using the energy.

While fasting, because you are more using energy rather than storing energy, your metabolism will be higher. This has been cleared with insulin therapy study. When insulin level is high, the metabolism decrease. This make sense because your body wants to store energy rather than use. Therefore, when insulin level is low from either fasting or low carb diet, the metabolism increases.

Growth hormone also increases when you fast. We have heard of fasting can decrease muscle mass and bone density. However, when you look at studies, fasting increase growth hormone and allow the body to become stronger, provided that you are exercising and eating healthy.

Lastly but not the least is autophagy. Autophagy is the process of body eliminating damaged or unnecessary cells to create the space of new and healthy cell to regenerate. Think of it this way. Let's say you want to remodel your kitchen and replace your cabinet. You will not be able to replace cabinet unless you take out the old cabinet. This taking out the old cabinet in out body is called autophagy. Fasting and autophagy has been receiving spotlight for cancer treatment.

Types of Intermittent Fasting

If you have searched online about fasting, you will see so many different types of fasting. From intermittent fasting starting from 12 hours to extended fasting that can last for 14 days.

Here, we will discuss more towards intermittent fasting for easier access.

It doesn't really matter how long. When you are not eating, you are fasting. Doesn't matter how long. Reason why there is a term "breakfast" is you are breaking the fast. It really has nothing to do with eating right after you wake up.

However, to have better benefit from fasting you may need longer fasting duration. It takes about 3-6 hours to bring the insulin level down after meal. Therefore, for the starter fasting, you should give at least 6 hours of gap between each meals. For example if you had first meal at 6am, you next meal would be 12pm, and last meal would be 6pm.

Now if you follow the example above, your last meal will be 6pm and next meal is at 6am the following day. This will be 12 hours fasting. This probably is the most manageable intermittent fasting.

Another popular intermittent fasting is 16-18 hour fasting. That would be from 6pm meal from previous day to following day 10am-12pm.

If your goal is to lose body fat, this may be a manageable, although slightly challenging, intermittent fasting to work on. To be fasted and suppressing insulin level for 16-18 hours, your body will be utilizing fat as energy level and metabolism will be higher than usual. It may take couple days to get used to and body to adapt, but fat loss will be happening.

24 hours fasting is popular one but relatively longer fasting. From this point on autophagy starts to kick in. Longer fasting is preferred for autophagy but if 24 hours fasting is practiced on weekly basis, autophagy can seem to be achieved.

What Happens When You Fast?

When you fast you will have several unwanted experiences and you will need to understand what they are and how to manage.

First obvious is the hunger. There is a hormone called ghrelin, which is hormone to promote hunger. However, this hormone secretion does not you are lack of energy. Think about it. We all have body fat and about 70% of US population has more than 30%. If someone weighs 200 lb and has 30% body fat, calorie stored in the body is more than 240,000 calories where most people's daily metabolic requirement is around 2000 calories. That is 120 days worth of calories! That means, 70% of population shouldn't be worrying about eating food for energy purpose for 2 month. Now, I'm not suggesting to fast for 2 month.

We get hungry, or ghrelin get secreted is mainly because of the eating habit. Managing this is hard because if you have been snacking on regular basis, the ghrelin has been programmed to secreted at those timing. This is something you will need to train. It takes about 14 days to retrain your ghrelin secretion timing.

Another things to keep in mind is consequence of keeping the insulin level low. One issue that I frequently hear is dizziness. When insulin is low, the body loses the binding site for the salt and become deficiency for salt and cause mineral imbalance, which leads to dizziness. Therefore, when you are fasting it is important to add more salt to the diet.

Personal Application of Fasting

Everybody's schedule is different. That means fasting timing may be different. Ideally, though, it is easier to skip meal in the morning. From personal fasting habit, I follow 6:30am breakfast, 12:30pm lunch, and 6:30pm dinner. So I'm fasting for 6 hours fasting between meals and 12 hour fasting from dinner to breakfast. However, I do workout 4-5 days per week so I divide my total food intake in those three meals.

The main focus for fasting for me is to give my body a to suppress insulin level, promote fat burning, and autophagy. Aside from that I don't have much time to snack during my work hours so the meal schedule actually help me eat without adding unnecessary fat.

Who Shouldn't Fast

There are people whom I advice not to fast.

First is someone who is pregnant and breastfeeding. If you are in that category, you will need food as energy and nutrients to provide for yourself and for the fetus.

Second is anybody under 18 shouldn't be worrying about fasting because of their growth. If the fat gain is the issue, you should be consider improving the quality of food rather than fasting.

Third is those who have higher stress. Whatever the stress factor is, their cortisol level is high and this may be contributing to fat and weight gains. Fasting, especially extended duration fasting (>24 hour) may lead to higher production of cortisol which may lead to higher production of insulin.

Lastly, you should always discuss with your doctors on whether you should apply fasting into your life if you already have underlying health condition.

Where Should You Start

If you are interested in adding fasting to your life the easiest fasting to start is 12 hours fasting. All you need to do is finish your dinner than fast for 12 hours to have next meal.

So for example, if you finished you meal at 8pm, then your next meal is at 8am. As long as you are not consuming any food or beverages with calorie will be fine. So, water, black coffee, tea, and bone broth will be ok.

Another thing you can practice is cutting out snacking. Doesn't matter what you consume during your snack but keep the main meals and consume nothing else in between.

Stay Healthy,

Kota Shimada