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4 Types of Fasting Diets Explained: Which is Best for You?

Fasting has quickly become the hottest trend in the health and fitness world. It’s easy to see why with a laundry list of health benefits like weight loss, longevity, cancer prevention, and more. 

Feeling the pull to try fasting but a bit overwhelmed? I feel you. With so many types of fasting diets out there, it’s tough to know where to start. This article will delve into four popular fasting diets so you can choose the right fit for you. 

So What Are Fasting Diets Anyway?


Simply put, fasting is abstaining from food for a period of time. While intermittent fasting is what’s all the buzz right now, fasting is nothing new. It’s been practiced for religious reasons for thousands of years. 

Some fasting diets limit food during certain hours, while others exclude solid foods entirely. They vary widely in intensity and duration, so no need to go full tilt your first go. The key is starting slowly and choosing the right one for your body and health goals. 

Health Benefits of Fasting (and How it Works)

Recently there’s been oodles of research on the health benefits of fasting. In fact, fasting is currently being researched by over 2,100 clinical trials

Studies show fasting may help:

The magic of fasting’s benefits revolves around autophagy, your body’s internal housekeeping. Just like your home would be a hot mess if you never took out the trash, the same is true for your cells. Autophagy (which means self-eating) sweeps up the wonky cells and recycles parts for cellular repair. 

Autophagy happens naturally during sleep. However, research suggests that fasting may induce autophagy while you’re awake. How? Well, digesting food uses energy. Eating three square meals a day means less energy is available for internal clean-up. Fasting changes that, kicking autophagy into action. This is critical since cell damage can lead to cancer, liver disease, heart disease, diabetes, infections, and other nasty health issues.

4 Popular Types of Fasting Diets

Now that you understand the health benefits fasting can deliver, let’s break down some different types of fasting diets:

1. Water Fasting

Fasting Diets

Water fasting is arguably the most intense of all fasting diets. As its name implies, this diet restricts all food, only allowing water. Water fasting is typically done for 24-72 hours. People water fast for all kinds of reasons including:

  • Religious or spiritual reasons
  • Prepping for surgery or medical procedure
  • Weight loss
  • Detox
  • Health benefits

Studies have linked water fasting with lowering risks of chronic diseases such as heart disease, cancer, and diabetes. However, water fasting is not for the faint of heart and can be risky if done for too long or without medical supervision. 

For water fasting, you have to drink more water than on non-fasting days. That’s because usually, part of your daily hydration comes from the water content in foods. During water fasts, aim for two to three liters of water a day. 

Water fasting can lead to weakness or dizziness, so it’s best done when you have some downtime to rest. Also, don’t go hog wild post-fast. Your body needs time to readjust to food, so break your fast with some easily digestible food like a smoothie or light meal. Overeating just after your fast can lead to refeeding syndrome, which can cause rapid changes in fluid and electrolyte levels.

2. Juice Fasting

Fasting Diets

Juice fasting, also known as juice cleansing, is a popular way to detox and shift your tastebuds to crave healthier foods. Juice fasting involves drinking several premade or DIY juices made of fruits, veggies, and herbs, along with plenty of water, tea, or other clear liquids. Juice fasts are typically done anywhere between 1-10 days.

Juice fast devotees claim they can support weight loss, improve skin, lower inflammation, trigger detox, and cut sugar cravings. However, currently, there’s not much scientific evidence to back this up. One study did find that juice fasting led to improvements in the gut microbiome. This can, in turn, lead to weight loss, but additional research is needed.

Juice fasts are a simple way to flood your body with loads of vitamins, minerals, and phytonutrients while giving your digestive system a break.  But there are some downsides. 

Because juicing removes the fiber from foods, drinking loads of juice can lead to nasty blood sugar spikes. Be sure your juice concoctions are about 80% vegetables and 20% fruit to prevent this. Choosing lower sugar fruits like lemons, limes, green apples, pears, and berries can help too.

Just as with water fasting, juice fasting can lead to weakness and dizziness, so you’ll want to take it easy. A juice cleanse is NOT the time to start a new workout routine! Also, be sure to ease into solid food slowly post-fast.

3. Intermittent Fasting Diet


Intermittent fasting (IF) isn’t so much about what you eat but when. Instead of recommending particular foods, intermittent fasting diets cycle through set periods of fasting and eating. So, in reality, it’s really more of an eating schedule than a diet.

Speaking of schedules, there are a variety of intermittent fasting options. Here’s a few of them:

Time-Restricted Fasting (16/8)

This is where you eat within a set window of time. The most popular form of this is 16/8, where you fast for 16 hours and eat within an 8-hour window. For example, you eat your first meal of the day at 10 a.m. and your last meal by 6 p.m. 

This form of fasting is one of the easiest, as a good chunk of your fasting window is spent sleeping. However, some people opt for more intense time-restricted fasts like 20/4, where you eat two meals within a 4-hour window and fast for 20 hours. 

5:2 Diet

With the 5:2 diet, you eat normally five days a week and pick two fasting days of your choice. On fasting days, you typically reduce your calorie intake to around 500 calories for women and 600 calories for men. However, some 5:2 aficionados avoid food entirely on fasting days. Regardless, be sure your two fasting days are not back to back.

Alternate Day Fast

This is a more intense version of 5:2, where you fast every other day. On non-fasting days, you eat normally, while you stick to around 500 calories on fasting days. Clearly, this is not a good choice if you’re new to fasting.

Stop Eat Stop Fast

This fast is the brainchild of fitness expert Brad Pilon. Stop eat stop involves 24-hour fasts done once or twice a week. Obviously, this is something you’d want to work your way up to and not for fasting novices. 

Spontaneous Meal Skipping

This is the most intuitive and mild form of intermittent fasting. Spontaneous meal skipping simply means you skip meals occasionally, whether you’re on the go or just not hungry. In essence, this is a spontaneous form of intermittent fasting and a good intro to get your fasting feet wet. 

4. Fasting Mimicking Diet


While intermittent fasting is the popular kid in the fasting world, the fasting-mimicking diet is the new kid on the block. The fasting-mimicking diet was created by Dr. Valter Longo, a cell biologist and longevity researcher. The magic of this diet is that it allows some food intake while “tricking” the body into thinking it’s fasting. 

This probably sounds too good to be true, but science backs this up. Dr. Valter and his team at the Longevity Institute of the University of Southern California conducted extensive research on how food restriction affects health and longevity. Based on those findings, he developed the Prolon Fasting Mimicking Diet, a five-day program with a precise micro- and macronutrient breakdown that nourishes you without being recognized as food

Basically, Prolon makes your body think it’s fasting while still consuming reduced amounts of food. If you want to reap the benefits of fasting but are intimidated by the whole “not eating” thing, Prolon is a good option. It contains plant-based, whole-food meals and snacks and is meticulously structured to keep you in a fasting state. Here’s what I mean:

  • Day 1 is 1,100 calories: 11% from protein, 46% from fat, and 43% from carbohydrate
  • Days 2 through 5 are 725 calories: 9% from protein, 44% from fat, and 47% from carbohydrate 

The 5-day meal kit comes with everything you need, including vegetable soups, bars, crackers, olives, drinks, and supplements. None of the ingredients are random. They’re all designed to increase autophagy, your body’s internal housekeeping that we covered earlier. 

Research shows fasting-mimicking diets offer a bevy of health benefits, similar to regular ol’ fasting, including:

  • Promoting weight loss
  • Reducing belly fat
  • Lowering inflammation
  • Balancing blood sugar levels
  • Lowering cholesterol

Which Type of Fasting is Most Effective?

best for you

Research shows all types of fasting diets reap health benefits. So really, the most effective one is whichever you can stick with! There’s a fasting diet out there for everyone. For fasting newbies, spontaneous meal skipping is a good place to start. 

Want a deeper dive into the wonderful world of fasting but could use some guidance? I got you.  This early spring 2022, I’ll be guiding a group Prolon fasting-mimicking diet! If you’re looking to maintain some healthy habits you started in early 2022, this is an amazing opportunity to cleanse out the holidays and get ready for swimsuit season.  

Whether your aim is to burn belly fat, lose that stubborn holiday weight, or lower your risk of chronic illness, fasting can help.  Get the support you need to make your health goals a reality — sign up for a 5-day Prolon fast here if you can’t wait for our spring Fast Week, or stay tuned for the launch of our Fast Week Prolon FMD sale in early spring.  We will announce via email and on social media:)

Yours in Health,

Dr. Amy

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Coreflex Wellness serves areas such as Aspen and Glenwood Springs. These areas include but are not limited to Snowmass, Carbondale, New Castle, Palisade, Grand Junction, Telluride, Durango, Montrose, Eagle, Edwards, Frisco, Boulder, and Denver.

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