If you’ve ever asked, “Is fasting healthy“, you’re probably looking for a definitive “yes” or “no” answer. Anyone who gives you that kind of black or white response is doing you a massive disservice.

The right question is, “Is fasting healthy for you, right now?” and the answer depends on a number of factors including:

  • Why are you fasting?
  • What benefits are you looking for?
  • For how long are you fasting?
  • What kind of fasting are you considering?
  • What is your mindset about fasting?
  • Are you healthy?
  • Are you well-rested?
  • Do you have a healthy relationship with food?
  • Do you have a consistent habit of eating well and using food appropriately?
  • Are you on any medications?
  • Are you under the care of a health professional?
  • How does your body respond to fasting?
  • Do you have a healthy response to hunger?

What is fasting?

Abstaining from fuel (energy in the form of calories) for health, spiritual or other personal reasons.

What are the different types of fasts?

We all fast. Between your last meal or snack in evening and your first meal or snack in the morning, you’re fasting! Whether it’s 8, 12 or 16 hours, that is a fast.

When it comes to eating versus fasting, it’s helpful to differentiate between two different states of the body: fasted or fed.

In a fed state, you’re either actively eating or in the post-prandial (after a meal) state where your body is digesting and absorbing what you last ate.

In the fasted state, you are not eating, your body has finished metabolizing the last items you ate, and your body is meeting it’s fuel needs from your fuel reserves (stored fat or stored glycogen).

I go into the different states in more detail in episode 037 of the Primal Potential podcast.

Intermittent fasting: Your overnight fast is an example of an intermittent fast. Intermittent fasts are generally less than 24 hours but please don’t get hung up on definitions. Do what you want to do and don’t worry about how to define it. The semantics don’t really matter.

Modified fasting: fasting mimicking diets fall into the category of modified fasts. In a modified fast, you might consume fuel, but you’re fasting from a certain kind of fuel. Most commonly, you’ll see individuals choose to voluntarily restrict protein for a set period of time to generate hormonal benefits. Or, you can consume only dietary fat for a period of time. This isn’t a true fast, because you’re consuming fuel (maybe from MCT oil), which is why it’s called a modified fast.

Extended fasting: Longer fasts measured in days versus hours. Personally, I have done two 5-day fasts and one 7-day fast. Extended fasting is not the same as starvation and you have a very different hormonal response to true fasting than to a very low calorie starvation diet. I go into the differences in your body’s response in episode 469.

What are the benefits of fasting?

The benefits of fasting depend on factors like the type of fasting, the duration of the fast and the health & mindset of the faster.

With that said, the benefits that are available to you include detoxification, healing, elimination of unhealthy cells, increased energy, decreased inflammation, improved insulin sensitivity, fat burning and much more!

What do people get wrong about fasting?

Primarily, fasting is not the same as crash dieting. Your body will not default to burning muscle. You will not slow your metabolism. For more on these myths and how your body actually responds to fasting, take a listen to episode 469 of the Primal Potential podcast.

Who should fast?

Individuals who have already created a baseline of consistently taking great care of themselves. Individuals who are free from the extremes of dieting and binge eating. Individuals who are open to learning more about their bodies and do not have medical conditions or prescription medications that would interfere with a healthy fast.

Who should not fast?

Anyone who is not yet consistently eating clean. Anyone on prescription medications that need to be taken with food. Type 1 diabetics who aren’t being monitored by a health professional. Anyone with an active eating disorder. Anyone with a crappy attitude. Anyone who is underweight or malnourished. Anyone who doesn’t want to fast!

What about women with thyroid conditions or other hormonal imbalances?

There is no one answer for this, I’m sorry. It’s individual. I am a woman. I have hormonal imbalances including Hashimotos. I find that fasting is wonderful for me. It makes me feel great physically and emotionally. I refuse to believe that any one thing is true for “all” people. There are too many other contributing factors like: your baseline diet. Your body composition. Your stress level.

The first thing I would suggest these women look at is: are you consistently eating well? Are you consistently making great food choices, avoiding processed foods and sugars? Are you consistently giving your body the fuel it needs and not giving your body more fuel than it needs? If not, start there.

I’d also suggest that these women consider: is your stress level managed? Are there things you can do to lower inflammation and reduce physical and emotional stress? Do those things first.

Then, give a 24-hour fast a try. Go into it with a great attitude and see how you feel. Learn from your body, not from someone else’s over-generalization.

Success tips for intermittent fasting:

Drink plenty of water! Prioritze sleep. During your fed periods (meals and snacks) avoid sugar, starch and processed foods. The blood sugar stability you create when you avoid those things will make your fast much easier! Remind yourself that

Success tips for extended fasting:

Get plenty of sleep. Minimize stress. Avoid strenuous workouts. Don’t complain. Don’t panic. Drink plenty of water. Use pink himalayan sea salt in your water or just plain on your tonuge. I go into this more in episode 469 of the Primal Potential podcast.

How do you endure the sensation of hunger?

Patiently. With practice and a healthy mindset. Effective strategies vary from person to person. What helps me might not help you. What helps me is reminding myself that hunger isn’t painful and it’s not permanent. If I overreact in response to hunger, I face a bigger emotional barrier than physical one. I like to ride out the sensation of hunger and see how long it lasts. When doing extended fasts, I’ll sometimes start the timer on my phone to see how long it takes for the sensation to subside. In my most recent 100 hour fast, the longest hunger pang lasted just two minutes and 4 seconds.

Beyond that, make sure you’re consistently eating well prior to the fast. Chronically stable blood sugar makes fasting easier. Drink plenty of water and use pink himalayan sea salt. Again, there is more on that approach in episode 469 of the podcast.

How to break a fast?

Moderately. If you’re thinking about binging before or after a fast, please do not fast. The way someone things about a fast, approaches a fast or ends a fast tells a lot about that person’s readiness for fasting.

If you’ve been doing an extended fast (longer than a day or two), let your body warm up. Break your fast with something simple like a little bone broth. Give it a few hours and then have something light.

Options to consider include: half an avocado, chicken soup or a handful of nuts. There’s no need to rush into it!

What not to do when you’re fasting:

Don’t panic or complain. You chose to do this, you can choose not to. You’re not a victim of your choice.

Don’t drink too much coffee. I’m a huge coffee fan and inadvertently consumed a ton of coffee during my first fast and felt super wired. Stick to 2-3 cups. Don’t overdo it!

Don’t exhaust yourself. Prioritize sleep!

Should you workout during a fast?

This is another one of those questions that doesn’t have a universal “yes” or “no”. This depends on you. It depends on why you’re fasting, for how long you’re fasting and how you feel. For example, if you’re fasting for healing or reducing inflammation, I’d encourage you to let your body rest. Skip the workouts and truly let your body pour it’s resources into healing. However, if you’re doing intermittent fasting, you’re probably just fine to workout. Look to find the answer that is true for you today, not the answer that is true in theory always. You’ll never find the latter.

My experience with fasting:

Episode 469: Is Extended Fasting Healthy

Episode 037: Intermittent Fasting & Overfeeding

Episode 307: Is Fasting Right For You?

Episode 310: 5 Things I Learned During My 5-Day Fast

Fasting Resources:

Chris Kresser on the Fasting Mimicking Diet

The Complete Guide To Fasting