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Is Intermittent Fasting Difficult? Here’s What You Should Know

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Last Updated on June 6, 2022

The long quest of finding the perfect, healthy diet and what is nutritious to consume has extended the search to when is the most appropriate and most beneficial time to eat during the day. Some nutritionists have had hard and fast rules, like no gluten or no eating three hours before bed. 

Over the last decade, specialty diets have emerged rapidly since not all bodies are created the same. It has been popular for people to be grazers for many years, eating five small meals a day instead of the traditional three squares.

However, many people are pushing that eating method aside since there is a new form of eating that goes along with the age-old tradition of fasting called intermittent fasting. 

What Is Intermittent Fasting?

Intermittent fasting is when a person chooses to eat during select hours of the day or specific days of the week. Intermittent fasting aims to give the body a long enough break from eating that it begins to burn fat. 

Unlike conventional fasting, where a person abstains from food and water over an extended time frame, usually partaking in a religious sacrifice, intermittent fasting is giving up food for parts of the day or maybe 24 hours at a time. 

It’s basically a more accessible version of fasting or an extended version of refraining from eating three hours before bed. While intermittent fasting, you can all several windows of open eating periods throughout the day. Or, you can break up a 24-hour fasting schedule into two days. 

Even so, there are a couple of different versions of intermittent fasting to choose from when you start a periodic abstaining program. Distinctive versions of intermittent fasting have various levels of reaching the fat-burning phase, called autophagy.

What Is Autophagy?

Autophagy happens during a fast and is a natural way for the body to protect itself from starvation. Autophagy is the process of the body consuming its own storage reserves. The Greek translation of autophagy is ‘The Body Eating Itself’. 

Fat and tissue, along with cells, get stored in little increments in your body every time you eat as a safety reserve. So when you fast for a lengthy period, the body will go into autophagy, removing the garbage cells to prevent starvation and eventually, will make you feel less hungry.  

So, is autophagy good or bad? Both. Too much autophagy can be unhealthy since the body will start feeding off the good stuff, like healthy organs and tissue. However, just the right amount of autophagy can have numerous health benefits on the metabolism and cells.

Current Studies

In 2016, Nobel Prize winner, Yoshinori Ohsumi, uncovered several health benefits that coincide with autophagy. Over the last several years, studies have exploded on all the potential health benefits that can come from intermittent fasting and reaching autophagy. The health benefits include:

  • Anti-inflammatory

  • Cancer Prevention

  • Mental Health Diseases 

  • Antiviral and Antibacterial Protection

Types of Intermittent Fasting

You can choose from 4 different types of Intermittent fasting. Each type of fasting has its own regimen, so it’s best to know how each one works before committing to one. Discovering which fasting method works best is a personal choice since everyone’s body is unique and reacts differently to food and the lack of food in their system.

The 16/8 Method

The 16/8 method is similar to the 14/10 method. The concept for both of these methods is the same. You can only eat during certain times of the day.

The lower number is when you can eat, and the larger is how many hours to fast. So, for example, the 16/8 is sixteen consecutive hours of fasting and eight hours of allowed eating time. The 14/10 method would be fourteen hours of fasting and a ten-hour eating window. It’s essential to maintain the same time window each day to keep the body on track.

The Best Windows for 16/8

The most common eating windows for the 16/8 method are as follows:

  • 7am until 3pm
  • 9am until 5pm
  • 12 noon until 8pm
  • 2pm until 10pm

For 14/10, you would simply add two hours to each window.

This method is popular and easy for many to maintain intermittent fasting without experiencing severe discomfort. The 16/8 or 14/10 way has plenty of health benefits on the body’s metabolism. In addition, these methods result in mild autophagy, which has been listed as safe for many individuals that don’t have any preexisting conditions. 

Side Effects Of 16/8

Although extremely popular, 16/8 has some temporary side effects when you start the program. However, in most cases, side effects disappeared after getting used to fasting. Common side effects include:

  • Hunger
  • Weakness
  • Fatigue

Famous 16/8 Results

Jennifer Anniston: Since 2019, Jennifer Anniston only consumes celery juice and coffee each morning. She saves eating solid foods until later in the day. She has claimed that she noticed the difference in how she looked and felt reasonably quickly.

Halle Berry: Sharing her relationship with intermittent fasting since 2018, Halle Berry explains that she doesn’t eat until 2 pm each day. Halle makes sure that she gets in nutrients and vitamins each morning but waits until the afternoon to eat solid foods. 

Chris Hemsworth: The superhero actor adheres to a 16/8 eating schedule and reduces his calorie intake.

Other Celebrities who practice intermittent fasting with the 16/8 method include:

  • Reese Witherspoon
  • Mindy Kaling
  • Scarlett Johansson

Alternate Day Fasting

Alternate Day fasting, also known as Up Day, Down Day fasting, is intermittent fasting every other day. The process is to eat regularly on days one, three, five, and seven. On days two, four, and six, you will only intake 500 calories. It equals out to be about 20%-25% of your average intake. 

Alternate Day fasting is known to be an easy fasting method that claims to have good results in terms of looks and feel. The downside is that a study concluded an increase in HDL, which is the bad cholesterol, in those that stopped Alternate Day fasting for six months. However, the upside is that Alternate Day fasting allows the body to lose weight and stay lean. 

After successfully maintaining 20% of your calorie intake, the Alternate Day fasting allows you to increase your calories. So, if you were losing weight at 500 calories every other day, you can advance to eating 600 calories. If you continue to stay lean, you can eventually increase up to a maximum of 60% of your regular calorie intake over time. If you start to gain, you will drop back to the last calorie count you were at while maintaining your weight.

Keeping track of your calorie intake in a food journal is one of the easiest ways to maintain and track your progress. In addition, health benefits are still viable from this type of intermittent fasting. Within a 12-month study, there was a substantial improvement in specific tissues of the body including insulin levels, blood pressure, decreased cholesterol, and reduced inflammation.

Side Effects of Alternate Day Fasting 

There are some side effects of Alternate Day Fasting. Most side effects will resolve after your body gets used to fasting, but be conscious of:

  • Hunger

  • Fatigue

  • Overeating on regular days

Famous Alternate Day Results

Ben Affleck: Ben Affleck has allegedly been doing this Alternative Day fasting for years. His fiancé Jennifer Lopez is also an intermittent faster, but she is more into 16/8 or 5:2 fasting. So together, the two might combine their fasting skills. 

Beyonce: The Queen B has been rumored to participate in Alternative Day fasting, but she has never confirmed or promoted any intermittent fasting methods.

Hugh Jackman: The Wolverine has been said to alternate between Alternative Day fasting and 16/8, depending on the role and if he needs to bulk up or slim down.


Researcher, Brad Pilon, created the Eat-Stop-Eat method. His research states that the time of day you consume food is more crucial than what you ingest.

The method includes fasting for 24 hours and then eating regularly for up to seven days before your following fast. You should only fast for a majority of 2 times a week with a couple of days of regular eating in between. Also, the way Pilon spaces out fasting will allow an individual to eat something every single day but have a 24-hour space between meals on a fasting day. 

For example, if you eat breakfast in the morning on a fasting day, you will not break your fast until lunch the next day. Pilon respects the ability to keep fasting flexible for individuals. Pilon’s book, Eat Stop Eat, believes this method makes losing weight easy. Fasting for an entire 24 hours sounds overwhelming when doing it all in one day, but it is mentally easier when being able to eat at least once a day. 

Eat-Stop-Eat requires a person to be in good health. People with preexisting conditions, like diabetes, pregnancy, or breastfeeding, should not do Eat-Stop-Eat. Fasting for 24 hours still involves staying hydrated with water during the fast. With other fasting methods, you are abstaining from solid foods only, but with Eat-Stop-Eat, fasting includes abstaining from other nutrients for a couple of days out of the week.

Side Effects of Eat-Stop-Eat

Eat-Stop-Eat has great success in losing substantial weight over a fair amount of time. However, Eat-Stop-Eat keeps food and nutrients from the body for an extended time, so it does come along with some side effects. The side effects include:

  • Hunger pangs

  • Sleepiness from a lack of energy

  • Irritability

  • Mental fog

  • Low libido

Famous Eat-Stop-Eat Results

Kourtney Kardashian: In 2018, Kourtney Kardashian went public with her love for intermittent fasting. Kourtney has developed the fasting method that works for her. She fasts for 24 hours once a week. After that, she incorporates 16/8, where she eats after her morning workout around 11 am and does not eat after 7 pm. To stay hydrated, Kourtney alternates drinking water and bone broth.

The 5:2 Diet

Is 5:2 Diet is a simple diet that resembles the Alternate Day diet, but is a lot simpler since it is only two days of watching your calorie intake. For five days, you eat a regular diet. Then for two days, you eat between 500 and 600 calories, but not in a row. You can choose three small meals or two larger meals on fasting days.

The 5:2 Diet allows you to pick any two days out of a week as long as they aren’t back to back. For example, you eat regularly Sunday, Monday, Wednesday, Friday, and Saturday. But on Tuesday and Thursday, you would only eat 500 to 600 calories for the day. The best part is that you can mix it up every week as long as you have at least one regular day of eating in between fasting days.

The 5:2 Diet doesn’t focus on what you eat, but on how you eat. However, eating junk food all day on regular days will surely eliminate the benefits of intermittent fasting. Increasing food consumption on regular days will also reduce your chances of success with the 5:2 Diet. Therefore, maintaining your standard eating patterns on regular days is essential. 

The 5:2 has shown to be just as effective at losing weight as regular everyday calorie counting. It has also improved insulin levels. In addition, the 5:2 Diet has helped individuals lose belly fat while causing less reduction in muscle mass.

Side Effects of The 5:2 Diet

There are only a few reported side effects from the 5:2 Diet that quickly resolve once the body becomes accustomed to intermittent fasting. They include:

  • Hunger

  • Weakness

  • Moving slower than usual

  • Overeating on regular days

Famous 5:2 Diet Results

Benedict Cumberbatch: For his role in the BBC’s Sherlock Holmes, Benedict Cumberbatch followed the 5:2 Diet to trim down. He felt it worked perfectly in achieving Sherlock’s body type.  

Gisele Bündchen: In her book, Lessons, Gisele Bündchen tells all about her intermittent routine. On her fasting days, she doesn’t eat until lunchtime as she prefers the two bigger meals a day instead of three smaller ones.

The Most Popular Fasting Method

The most popular method of intermittent fasting is the 5:2 Diet. Although the 16/8 method is a close second, the 5:2 Diet has been said to be the easiest to conform to when trying to lose weight. Instead of starving the body and mentally challenging oneself with extended fasting, the 5:2 Diet allows the body to appreciate what it has and adapt to a lower calorie diet twice a week.

The Health Benefits of Fasting

Many groundbreaking studies are currently being conducted on the benefits of intermittent fasting. Gene expression and cellular repair have been discovered as some of the significant benefits of intermittent fasting.

Studies on intermittent fasting continue to focus on the effects on the brain and the prevention of dementia. Studies also move forward with strong momentum on the positive impact of intermittent fasting and its part in reducing cancers within the body. 

A recent study has shown that intermittent fasting can increase the lifespan of fruit flies and rodents. It is still unknown if it extends human life. However, the following benefits have already been studied and proven to be fact:

  • Weight Loss

  • Health Prevention

  • Anti-Aging

  • Reduction of Insulin Resistance

  • Reduce Inflammation

  • Increase LDL

  • Increased Autophagy

  • Reduce Oxidative Stress

  • Reduce Blood Sugar Levels

  • Increase Human Growth Hormone (HGH)

Side Effects

As you already know, intermittent fasting has side effects, like hunger, sleepiness, and weakness, which usually dissipate when the body gets used to fasting. However, symptoms that last longer than the first or second week should be brought up to your doctor.

In addition, intermittent fasting can change your body’s hormones and chemistry, so it is imperative not to harm your system. 

If you have a preexisting condition, speak to your doctor about intermittent fasting before trying it. Intermittent fasting isn’t suitable for everybody. 

Food for Thought: Intermittent Fasting 

Intermittent fasting is an old method with a new twist and a lot of popularity that can be modified for individual’s lifestyles. However, it is always best to check with your doctor before starting any new method. Intermittent fasting isn’t for everyone, but it can possibly have many health benefits for those whose bodies can tolerate it.


Dr. Ananya Mandal, M.D. What is Autophagy?

Brian J Altman, Jeffrey C Rathmell, Autophagy: not good OR bad, but good AND bad.

Medically reviewed by Daniel Murrell, M.D. — Written by Sara Lindberg, Autophagy: What You Need to Know.

Monique Tello, MD, MPH, Eat only every other day and lose weight?

Adda Bjarnadottir, MS, RDN (Ice) The Beginner’s Guide to the 5:2 Diet

Ansley Hill, RD, LD on January 7, 2020 — Medically reviewed by Jillian Kubala, MS, RD, Nutrition Eat Stop Eat Review: Does It Work for Weight Loss?

Kris Gunnars, BSc — Medically reviewed by Katherine Marengo LDN, R.D., Nutrition, 10 Evidence-Based Health Benefits of Intermittent Fasting

Yuanshan Cui, Tong Cai, Zhongbao Zhou, Yingmei Mu, Youyi Lu, Zhenli Gao, Jitao Wu, and Yong Zhang, Health Effects of Alternate-Day Fasting in Adults: A Systematic Review and Meta-Analysis

Press Release - The Nobel Prize in Physiology or Medicine 2016 retrieved from


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