9 Intermittent Fasting Side Effects You Need to Know

This post may contain affiliate links. Please read our disclosure for more info.

One of my favorite health hacks is a form of calorie restriction called intermittent fasting (IF). While there are several different types of intermittent fasting, I prefer the 16/8 method.

The 16/8 intermittent fasting schedule begins when you stop consuming calories and then refrain from eating anything for 16 straight hours.

Many people prefer (myself included) to start an intermittent fast sometime after dinner (normally 8:00 PM for myself). Then after the 16 hours of fasting are complete, you can begin eating for the remaining 8 hour window.

We certainly don’t recommend eating for 8 hours straight, but this form of fasting has an 8 hour block where your calories can be consumed.

Normally when I do intermittent fasting, I will stop eating at 8:00 PM and then start back by eating lunch around 12:00 Noon. Then I eat dinner sometime between 5:00 PM and 7:00 PM.

From there … the intermittent fasting cycle starts again with calorie restriction starting at 8:00 PM.

Typically, people who follow this intermittent fasting routine will limit what they put into their body (while fasting) down to – black coffee, tea, and water.

Note – This is just one form of intermittent fasting and happens to be the protocol that I follow. For more information, check out our – Guide to Intermittent Fasting for Beginners.

9 Possible Side Effects from Intermittent Fasting

Why Do I Go Through the Hassle of Starving Myself for 16 Straight Hours?

For those of you whom have never tried intermittent fasting … you may be wondering why I would go through such a hassle of not eating for 16 straight hours?

The main reason I do intermittent fasting is that it helps with my autoimmune disease … which is psoriasis. Intermittent fasting is one tool in my arsenal that helps minimize my psoriasis.

You’re likely also wondering if intermittent fasting safe? And are there any side effects to doing intermittent fasting (good or bad)?

Today I would like to share from my own personal story the intermittent fasting side effects I have discovered.

Below you will find 9 of the most amazing side effects I have discovered (so far) from intermittent fasting.  Most of them are good but there are a few you need to be aware of.

Let’s get started!

Amazing Intermittent Fasting Side Effects

Whether you do intermittent fasting for the health benefits, religious affiliation, or some other reason … there can be some amazing side effects. While most of these side effects are beneficial, there are some that may not be so positive.

Over the past couple of years of following a 16/8 intermittent fasting schedule, I have encountered many benefits.

There have also been a few downsides to following intermittent fasting … but most of these are manageable and worth all of the positive side effects.

I’ve put together a list of 9 intermittent fasting side effects that you should know. There are likely a lot more than this list … but these are the things I have noticed.

My hope is to continue updating these side effects from my own personal experience … as I continue to use intermittent fasting to improve my health.

Here is the growing list of intermittent fasting side effects I have experienced over the years.  Please feel free to share your own intermittent fasting results in the comments below!

1. Fewer Autoimmune Symptoms

This is from my own perspective … but when I am on a fast, I have fewer symptoms related to my psoriasis. Or better put … my psoriasis isn’t as inflamed.

It seems that the longer I go without eating food, the better my psoriasis is to manage. It certainly doesn’t go away, but it is much more tolerable. I don’t itch as much and my skin feels a lot softer.

Intermittent fasting has been the most effective treatment for my psoriasis that I have found thus far … which is why I have started to experiment with a 24-hour fast. The longer I can go without consuming food, the better I feel.

When I have bad days with my autoimmune disease, I almost always turn to intermittent fasting to get my psoriasis symptoms back under control.

Even if you don’t have an autoimmune disease, intermittent fasting gives your organs time to recharge. Fasting allows important organs like your liver and kidneys an opportunity to rest and detox … which has been crucial in my health journey.

On the other hand, when you are constantly eating, these organs just don’t have time to take a break and recover. When I slip and find myself eating all of the time, my psoriasis is usually at it’s worst.

So that is when I turn to intermittent fasting for the positive side effects.

2. Less Food Cravings

Speaking from first hand experience … intermittent fasting has really curbed my appetite. This likely won’t happen overnight for you, but given some time and patience … many of your hunger cravings will eventually go away.

I have found that when I fast and still eat a nutritious lunch and dinner, there are no late night snack cravings at all. Just for reference … when I do intermittent fasting, I skip breakfast. For more information about my intermittent fasting results, you can check here.

When I fill up on healthy fats and lots of nutrient dense vegetables at dinner … I feel satisfied and rarely crave sugary foods and snacks, especially at night.

Usually the two meals I eat during the day (lunch and dinner) are more than enough to fill me up.

Following an intermittent fasting protocol is a form of calorie restriction, which can help in weight loss. But the cool thing about this method is you will be restricting calories and won’t even realize it overtime.

I like to think of intermittent fasting as a way to train your body to NOT want to eat all day long … which is what many following the American Standard Diet have been taught to do.

Our bodies are just not meant to be constantly eating. Intermittent fasting is a tool for you to use to take back control of your diet.

3. Make Other Healthy Choices

Intermittent fasting can can be contagious. No you won’t catch any crazy disease or anything like that.

What I mean is that by following an intermittent fasting protocol … you will want to become healthier. Fasting can lead to many other healthy activities if you allow it to happen.

For example, when I am fasting I have a lot more energy. That sounds counter intuitive but it’s true. More energy pushes me to do other healthy activities like exercise more.

In addition to getting more exercise, I usually want to eat a lot healthier when I am following intermittent fasting. Typically I will try and follow the Whole30 program while I am intermittent fasting. Or at a minimum … I try and follow a paleo like diet.

I will also fall asleep a lot easier when participating in intermittent fasting. And it is good quality sleep that isn’t broken up throughout the night.

My stress levels are reduced when I am fasting. By not eating breakfast, most days I am taking a decision out of my routine of what to eat each morning.

All of these healthy side effects are an indirect result of my fasting efforts.

While intermittent fasting, I make healthier choices because I feel better and want the healthy benefits to compound.

Intermittent fasting just has a way of triggering these other healthy choices in my life.

4. Weight loss is Likely

While not guaranteed … you will probably lose some weight when you start intermittent fasting. It worked for me recently when I lost almost 5 pounds in just one week following a 16/8 intermittent fasting schedule.

If you stop and think about it … this really makes logical sense because of calorie restriction.

It’s really hard to continue eating the amount of food that you are used to … especially in a short time window. And since most of those nasty nighttime cravings are gone (see #2), it will be much simpler to eat fewer calories.

Consuming fewer calories means eventual weight loss … probably. Remember everyone is different, but there is a good chance of losing some weight from intermittent fasting.

How awesome is that? Weight loss will likely be a beneficial side effect of intermittent fasting!

5. Watch Out for Dehydration

Okay … so not everything is all nice and rosy when it comes to intermittent fasting. One of the negative side effects of fasting that I have discovered is the higher chance of becoming dehydrated.

Drinking Water When You Wake Up is a Great HabitThe type of fasting I am talking about here isn’t the kind where you don’t drink water. In fact, I encourage myself to drink more water than I normally might while in a fasted state.

First of all, drinking water will help reduce any hunger pains you experience while fasting (see #2 again).

Second … I am overly cautious about getting dehydrated and suffering from detox headaches while fasting. So I make sure to drink plenty of extra water.

If you are looking for motivation on drinking more water during the day … might I suggest adding a daily healthy habit to your routine to keep yourself hydrated?

For example, I recently started a morning ritual of drinking 12 oz. of water first thing when I wake up each morning … no matter what. This helps my body get going and aids in digestion.

From there I make a goal of drinking water totaling half of my body weight in ounces every day. I try and front load more of my water intake during the morning and afternoon. And then let up some towards the evening.

Why do I let up in the evenings? Sleep!

I’m trying hard to focus on getting 8+ quality hours of sleep each night. Drinking too much water before bed ends up causing multiple bathroom trips during the night.

Just be sure to watch out for dehydration if you start intermittent fasting by taking preventative steps to drink more water during the day.

Note – I also drink black coffee (see #6) and tea while fasting in addition to water.

6. Be Careful to Not Drink Too Much Coffee

This is a side effect of intermittent fasting that I often fall victim to.

Since I am restricting food during my fasting hours, I am only allowing myself water and black coffee during those times. I will also occasionally have tea but I usually prefer coffee.

Sometimes (most of the time actually) I drink way to much coffee … because it acts as my fall back crutch when I am restricting food during a fast.

Even though my body doesn’t necessarily feel hungry while I am fasting anymore … I still treat drinking coffee as my reward.

I have found myself drinking 4 to 5 cups of black coffee during the mornings when I am fasting … because I tell myself it is okay.

While drinking black coffee has plenty of published benefits (especially for your liver and kidneys), drinking too much caffeine can have other impacts.

I probably won’t be giving up on coffee anytime soon (unless I need to for the Autoimmune Protocol) … but I need to be aware of how much I drink while intermittent fasting. If I drink a couple of cups of coffee while fasting, then I need to switch to straight water for a while to lower my caffeine consumption.

Most experts believe that drinking black coffee is allowed in intermittent fasting … and I agree. But just make sure to not overdue it on drinking it.

7. Your Life Will Become Simpler

Believe it or not, but one of the biggest benefits or side effects of intermittent fasting … is that your life will become simpler.

Your probably saying … “how can skipping breakfast make my life easier?”.

Assuming you are following the 16/8 intermittent fasting protocol and are eating between 12:00 Noon and 8:00 PM (or something similar to these hours) … you would be skipping breakfast.

This means one less choice in your day by eliminating the decision of what to eat for breakfast.

It may sound silly … but eliminating the need to decide what to eat for one meal per day can remove stress from your life.

I’ve read where some people don’t even start intermittent fasting for the health benefits … but rather to skip a meal and make their day simpler. They remove one decision from their lives which has a positive overall impact.

One less choice in your day means a simpler life.

8. You Will Probably Start Saving Money

Just like with losing weight, there is a very good chance you will save some money as a result of intermittent fasting.

It is pretty simple really … you’re going to likely eat less food during the day which will be cheaper in the long run.

Most likely if you are skipping breakfast you will save money by not getting that breakfast sandwich on your way to work. Or that muffin from the local bakery.

Hopefully your overall eating pattern will be improved too and you will cook more of your meals at home. There is no doubt that cooking from home will be much cheaper than eating out all the time.

Now, I wouldn’t necessarily start intermittent fasting just to save money in your budget. However saving money is a likely side effect of intermittent fasting that can’t be ignored.

9. There is a Chance You Could Overeat

Even though most of the time my hunger pains go away while fasting … it doesn’t necessarily mean I won’t overeat later in the day.

For example, let’s say that I fast from 8:00 PM on a Sunday evening until 12:00 Noon on Monday. I don’t want to completely kill the benefits of a fast by overeating on unhealthy, processed foods.

After restricting calories for an extended time period (like in a 16 hour fast), I have been known to overindulge in eating too much food … as a way to compensate. While I don’t always fall into this trap … I need to be aware of it happening.

So be conscious of not overeating and cancelling out the benefits of intermittent fasting.

For those of us who are already fasting, we’ve all probably been guilty of overeating still while doing IF

Is Intermittent Fasting Safe?

So now that we have covered many of the side effects (mostly benefits) that you could expect from intermittent fasting, I would like to share my thoughts on a common question –

Is Intermittent Fasting Safe?

I would like to begin my response by saying that I am not a doctor, nurse, or anyone with the background to give you advice on your health. So when I comment about intermittent fasting, it is for pure entertainment purposes only. These are the experiences that I have lived and learned and I am simply sharing my story. It is up to you to decide what best works for your own health. And it never hurts to talk to your doctor before you begin a program like intermittent fasting.

All that being said … yes I believe intermittent fasting is safe … at least for most people.

I think that most Americans could do well by skipping a meal once a day and be just fine.

But I would like to stress not giving up water and to make sure you are staying hydrated. Personally, I don’t do water fasts or week long fasts.

I’ve never has any issues while intermittent fasting … which pretty much means that I just don’t eat breakfast most days. I start fasting at 8:00 PM, sleep through the night, skip breakfast, and then eat a healthy lunch.

While I am fasting, I will drink a cup of herbal tea in the evenings, water when I wake up and through the day, and black coffee.

So for meintermittent fasting is very safe. The only problems I have are periodic hunger pains in the mornings which are minor.

While I feel intermittent fasting is safe for me, I don’t believe it is healthy for my kids (all under 18). And I wouldn’t push my wife to do intermittent fasting if she were pregnant.

But otherwise, I don’t see any issues with healthy adults following along with the 16/8 intermittent fasting protocol.

Here is a resource with a bit more technical reason why intermittent fasting is safe – How to Do Intermittent Fastingby Yuri Elkhaim

So what are your thoughts on intermittent fasting?  Do you think it is safe?  What benefits or side effects (negative ones too) have you noticed from your own experience with intermittent fasting?

Click Here to Leave a Comment Below 0 comments