Intermittent Fasting Pros and Cons as a Weight Loss Diet

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Intermittent Fasting: Is this trending diet technique too good to be true? Decide for yourself with our general introduction and explanation of pros and cons for using intermittent fasting (IF) as your new weight loss method.

While the trend of intermittent fasting has experienced a boost of popularity in recent years, fasting for health benefits is a practice that has been around since ancient times.

We’ve all heard the old adage “feed a cold, starve a fever” and there’s real truth in this! In times of true illness, our desire to eat naturally diminishes, allowing our body time to heal itself while in a fasted state.

Autophagy & Health Benefits of Intermittent Fasting

As intermittent fasting gains popularity, we are learning more about fascinating fasting health benefits; particularly something called autophagy.

Autophagy is the practice of how, while in a fasted state, our body has time to repair damaged cells and rebuild healthier new ones.

The video below offers a quick explanation of this process in more detail:

Autophagy and other health benefits may be reason enough to give intermittent fasting a try. Improved brain health, anti-aging benefits, improved digestion and cardiovascular health have all been credited to intermittent fasting.

Some studies have even shown that fasting can reduce neuronal dysfunction from neurodegenerative diseases like Alzheimer’s (check out this post from The Synchro Life for more information about the health benefits of intermittent fasting).

However, today we’re focusing largely on the pros and cons of intermittent fasting as a diet/weight-loss method.

Sure there might be some awesome health benefits, but will Intermittent Fasting really help us lose weight?

What Exactly is Intermittent Fasting (IF)?

First off, what is the basic idea of Intermittent Fasting (AKA “IF”)? As a diet method, Intermittent Fasting is the practice of choosing to go without food and/or drink intermittently or for varying periods of time.

Intermittent Fasting Times & Hours: Pattern Options

There are a number of different patterns would-be fasters can choose from, including:


With this plan, participants are allowed to consume a minimal amount of calories (500-600) 2 days each week (may be consecutive days or not) and then eat normally the other 5 days.

A variation of this plan includes true fasting (no calorie intake; just water and plain coffee or tea) for the 2 days. Some studies show this version to be about as effective as a traditional calorie-reduction diet plan.

EOD (Every Other Day)

Also known as 4:3, this plan works similarly to the 5:2 plan, but includes 4 days of regular eating alternated with 3 days of fasting. Choose to consume 500-600 calories one day, then eat normally the next day.

Variation: alternate a day of true FASTING with a day of FEEDING (eating normally). Considered a more difficult way to fast, this method requires the ability to switch eating habits back and forth daily and some people may struggle with the UPS and DOWNS of this method.


This plan focuses on hours rather than days. This version of IF involves fasting for 16 hours each day, say from 8pm-12noon, and then eating normally from noon-8pm.

This approach seems to work well for beginners since the bulk of the fasting hours occur while sleeping. Upon awakening, 16:8 fasters can enjoy black coffee or tea and hold out until noon, before eating.

The fasting benefit here is in giving the body a long enough period of time (at least 12-16 hours) to deplete its supply of insulin as its energy source. Searching for more energy, the body is able to switch to its fat stores as another source, resulting in weight loss as a side effect!



With this approach, get ready for a complete fast for 24 hours, one or 2 days each week.

Fasters pick a particular time or meal and upon completion of that meal, begin fasting, consuming only water, black coffee, or plain tea (known as a “clean” fast) until the same time the following day, when they can resume eating normally.

Some may wait a day or 2 and Eat-Stop-Eat again. Both calorie reduction and the benefits of insulin reduction are at work with this method.


This may not be a true form of fasting, but is a gentle intro to the idea of eliminating traditional “3 meal-a-day” thinking. Followers can choose to skip any meal they like and vary their choice as they go along.

Considered a beginner’s approach, this plan allows flexibility, some calorie reduction, and – depending on which meal is skipped – may include some fasting benefit if enough hours go by before the next meal is consumed.


This most extreme plan has several variations. Some followers call it “OMAD” or One Meal a Day, allowing for a window of time each day when just one feeding is allowed. Others refer to it as the Warrior Diet, (created by Ori Hofmekler) with the idea of “undereating” throughout the day and then “overeating” or feasting (as in Warrior times) during a set window of 4 hours or so.

The idea of allowing your body to sort of “detox” from food and then learn to efficiently process food quickly during a short feeding window, adds health benefits to this weight-loss technique.

Advantages of Intermittent Fasting

Here are our top 5 pros for why you may want to give intermittent fasting a go!

1) Intermittent Fasting Flips Your Fat-Burning Switch On

As a weight-loss tool, IF gives your body a chance to “flip your metabolic switch” from operating on insulin to operating on fat. And we all know that the key to weight loss is burning that fat.

It is impossible for our bodies to be both insulin burners and fat burners at the same time, so by fasting periodically, we allow our body enough time to deplete its insulin stores (glycogen) and look for an alternative energy source.

What is that source? You guessed it: our body’s own beautiful fat, just waiting to be burned!


When we eat, we increase insulin, which is the hormone that tells our body to stock up and store energy. We need just a tiny amount of insulin as energy to function each day, so insulin efficiently makes sure that the bulk of what we consume can be stored away, as glycogen (or fat) in case we need an energy source at some other time.

As long as we are eating, we are adding to that storage supply and our body really has no need or means to tap into that stored energy.

So you might ask…why not just cut calories or quantities of we eat? Dr. Jason Fung, author of The Obesity Code, explains that it isn’t just a calories in, calories out issue. The body is too smart for that and will simply reduce its need for energy if we just reduce calorie intake.

Fasting gives the body the time it needs to deplete its insulin stores, allowing us to turn to our stored fat as energy.

Dr. Fung explains this fat-burning process in the video below:

2) Intermittent Fasting Provides a Slow, Stable Weight Loss 

While some people experience quick results, most people using IF will enjoy a healthy gradual loss of 1-2 pounds per week.

This indicates true loss of fat as opposed to only water weight loss, or worse – muscle loss. This slow, healthy approach brings us to a state known as “fat adaption”, as explained in this video by Edward over at FledgeFitness:

The first phase of this process can take 2-3 weeks as the body depletes its glycogen stores and begins to switch to using fat as its energy source. Weight loss is slow as the body adjusts to this new energy source.

He explains that IFers eventually learn to “read” their bodies’ signals, fasting becomes much easier, and eating sensibly during feeding times becomes second nature. The body adjusts and no longer craves large amounts of sugar and carb-dense foods.

3) Intermittent Fasting is a Flexible, Affordable Plan

Followers can pick from a variety of methods to mix and match approaches. No special menus or fancy expensive foods are needed.

While some IFers choose to eat low-carb when not fasting, there is no requirement to do so. Calorie and macro counting are not required either.

4) Exercise is Optional 

That’s right! Most IF plans do not require a strict exercise regimen, although many IFers end up with more energy and choose to exercise to further speed up their weight-loss and build muscle.

Other IFers enjoy weight loss with little or no exercise at all and even see their bodies take new shape and lose stubborn fat as the process of autophagy naturally works its magic.

5) No Deprivation – Eat What You Want!

Because no foods are off limits, IFers take comfort in knowing they will get to eat all the foods they love once they finish their fast.

No deprivation means no sense of desperation or failure and less negative self-talk! No “I will never be able to eat bread again!” and “I can’t believe I just ate a cookie, I’m a failure”. Cookies and bread are allowed when not fasting (in moderation, of course).

feasting fasting


Disadvantages of Intermittent Fasting

Sounds great, right? But like every diet plan there are some negatives to consider. So here are our top 5 cons when looking at intermittent fasting as a diet / weight-loss method.

1) Intermittent Fasting Requires Total Compliance

One cannot “sort of” fast. It must be done completely and properly to be effective.

For most IF plans, this means that, for whatever time period you have chosen to fast, you may only consume water, black coffee, black tea, or plain seltzer water.

No cream for your coffee, no gum chewing, no flavors, no diet sodas. Some plans do put some items like lemon wedges in a “gray” area, but most agree that anything that could possibly spike an insulin response and certainly anything that gets digestive juices flowing, is off limits.


A “clean” fast for a period of 12, 14, 16 hours or longer can be a challenge and some people will give up before they make it past those first few difficult days. Still others might not even try, thinking it is beyond their realm of capability.

Breaking your fast with even just a cracker or a tiny bit of food, compromises this diet because it sends the body back into insulin burning mode, starting the clock over again and defeating the purpose of the fast.

2) Fasting is Often Misunderstood and Frowned Upon

Dieters choosing this approach really need to be confident in the face of naysayers who will attack IFers with statements like, “but breakfast is the most important meal of the day!” and “you’re going to ruin your metabolism if you don’t eat 6 small meals”.

Many IFers have not done their research, and so they end up caving in the face of opposition—and there is a lot of opposition out there!

Check out this Myth-Busting article explaining just these types of roadblocks IFers face.

3) Dreaded Plateaus Are Very Real with IF

Just like many other diets, IFers report a level of success followed by a period where weight-loss stalls.

If you practice Intermittent Fasting the same way, day in and day out, your weight loss will likely plateau. Our bodies adapt to just about anything, and fasting the same way every day or week is no different.

Many IFers also experience an initial ability to eat to their heart’s content during their feeding times and still enjoy weight loss. But as the body adjusts, the volume of food one consumes can affect results.

If fasters don’t remember to eat just to the point of satiety, insulin levels will stay elevated throughout fasting periods, resulting in a stall to weight loss.

A plateau also crops up when poor food choices and “empty calories” are consistently chosen over nutrient dense, healthy- fat foods. If you’ve reached a plateau and are having a tough time breaking through, be sure to read Gin Stephen’s (author of Delay, Don’t Deny) plateau-busting tips here.

4) Intermittent Fasting Can Be Inconvenient

If you have a fasting time that coincides with lunch dates, family mealtimes, or other life events involving food and drink, intermittent fasting can be difficult to practice. Adjustments and advance planning may be required to keep you on track.

5) Fasting Isn’t For Everyone

Although it is reported to be a safe approach for many people, always check with your doctor before starting any rigorous diet plan. Dr. John Berardi explains that this diet is not for women who are pregnant, or for people with an eating disorder.

So there you have it! Do the PROS outweigh the CONS for you? Which way do the scales tip for you? Have you tried this approach? Be sure to comment below and share your experiences!

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about the author:
Meg Mars
Meg is a writer who is passionate about healthy eating. From Whole30 and South Beach Diet, to paleo and intermittent fasting, she's experimented with several healthy eating regiments and is passionate about helping readers find the perfect food plan match for their lifestyles.

3 thoughts on “Intermittent Fasting Pros and Cons as a Weight Loss Diet”

  1. This is am amazing article about IF. As a faster, it is difficult to explain the IF concept to other people. This concise article will make a lot of info easy to “digest”!

  2. This is so interesting. Thank you! I was hesitant to try IF but after reading more I think it’s time to give it a shot!

  3. Great article on IF. I started 4 months ago and don’t think I will ever go back to my old way of eating. I lost 10 pounds by the 3rd month, reached my goal weight (actually go under it often) and am maintaining with little effort. I never thought I’d have enough energy to work out while fasted but as long as I keep drinking water, I have plenty of energy.
    I’m also doing this for the autography benefit since I went through breast cancer 7 years ago and want to make sure I stay cancer free.
    Ihave noticed that my skin is much better. This is the first time that i don’t need to wear makeup to cover sun damage spots on my face.
    I bounce around between a daily fast of 16:8 to 18:6. I probably eat fewer carbs than I used to but I still eat them and some sweets. I like that I don’t need to deprive myself of anything. But if I do overdue it, I know I can bounce back with a longer fast the next day or two. However it is easier to stay consistent as I notice I feel hungrier the day after eating carbs and sweets. I’m learning more about how foods effect me and I finally feel in control of the way I look and feel.
    Love this new lifestlye!


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