All About Intermittent Fasting

Before we dive into this juicy topic, please note: this post includes my personal opinions, coaching points and practices as a NASM Certified Personal Trainer, Women’s Fitness Specialist, PN L1 Nutrition Coach and L1 Sleep, Stress Management and Recovery Coach.

I am not a doctor, and I highly recommend you consult your medical professional and/or a registered dietician to discuss intermittent fasting and what might be the best path for you.

Oh man, I’ve been wanting to cover the topic of Intermittent Fasting for awhile and put it off over and over again. It’s not the easiest subject to discuss, and it’s proven to be controversial with alllll of the different opinions, practices and mispractices out there.

Everyone has an opinion and everyone is an expert, right?

I took the easy route and skipped over what seemed like a daunting task for a bit, but I think it’s time to address thoughts, opinions, and if this nutrition practice is appropriate for you and your goals today.

This topic comes up often in coaching, so I hope this post helps you with some clarity on what IF actually entails, and if it’s the journey that is right for you and your personal goals.

Let’s dive in!

First, let’s rewind a beat and answer the question you might be asking right now:

What is intermittent fasting?

Intermittent fasting (IF) is the practice of occasionally going for extended periods without eating, sometimes 12+ hours at a time. There’s also intermittent energy restriction (IER), which is occasionally eating significantly less energy than needed.

Both IF and IER are concepts that have been for a long time. Humans have fasted throughout history, whether it’s during the typical night’s sleep or during longer periods of time of food scarcity. And then, of course, fasting is present for religious reasons for days or even weeks at a time in order to prayerfully seek answers or observe something important to you.

Basically, the practice of fasting is nothing new, but the concept has become newer and wildly popular when doing so specifically for the goal of supporting weight and fat loss.

There are many different IF schedules to pick from like 16:8, 20:4, 5:2, among others.

But does it work? What are the pros and cons? And is it for you?

Frequently Asked Questions

Here’s what you should know before you decide if intermittent fasting is something you’d like to pursue, along with some frequently asked questions and answers!

Is intermittent fasting healthy?

The benefits of fasting largely stem from calorie restriction. When you fast, you obviously eat less than normal, or nothing at all. Depending on how long you fast (especially regularly), your blood sugar, insulin, resting heart rate and blood pressure can all decrease.

By 8-12 hours of fasting, your body has cleared out and used the nutrients from your last meal. Your body goes from using “outside sources” of energy (the meal) to “inside sources” (what’s already stored in your body), and shifts into a fasted state.

By 12-48 hours, your liver and kidneys start making glycerol and free fatty acids, and your body shifts into a state of ketosis, when your body burns fat for energy instead of glucose.

Anything after 48 hours shifts your body into starvation-mode, and – in my opinion – is not something anyone should practice regularly.

So, fasting in appropriate windows of time and taking feedback from your body on how you feel while, during and afterwards can be a healthy tool.

But it’s tricky and there are downsides, too.

What does it do to my metabolism and hormones?

Against many beliefs (including my own, initially), IF probably won’t mess with your metabolism too much. Please note, however, this answer is strongly based off of the fact that there is a difference between fasting and starving yourself. Fasting is usually going without food long enough to trigger the body to dip into stored energy (usually 8-48 hours), and starving is a state of extreme nutrient and energy deprivation that can have fatal consequences. Fasting is not starving.

That said, studies have shown that IF could benefit males more than females due to hormones that regulate key functions like ovulation, metabolism and even mood. These functions are highly sensitive to energy intake, so changing how much or even when you eat could potentially impact reproductive hormones and other health issues. So … definitely check with your doctor and OB/GYN if you’re curious and have further questions there.

What do the numbers mean when saying 16:8, 20:4, 5:2, etc.?

There is no one-size-fits-all fasting schedule that works for everyone. The effectiveness of any fasting schedule depends on the person following it and their individual factors like schedule, preference, physical demands and more.

As far as the numbers go, the number : number ratio describes how many hours you’re fasting to how many hours you’re eating, or in some cases, how many days you’re eating to how many days you’re fasting.

For example, 16:8 means you’re confining your eating to 8 hours of the day, and fasting the other 16. 20:4 means you’re fasting for 20 and eating all of your food within 4 hours of the day, and 5:2 means you’re eating normally for 5 days out of the week, then fasting for 2.

I know, it can seem confusing and there are a lot of options to try. The best way to find what works for you is to experiment and really listen to your body and hunger cues.

Who should and who shouldn’t try IF?

Getting the basics of nutrition fundamentals down first is more important than any type of nutrition frequency or pattern. While studying with Precision Nutrition, I learned fundamentals considered to be “Level 1” include the greatest hits of healthy, long-term practices like:

learning to prep, prepare and balance your plates
regulating eating behaviors
choosing high-quality foods often
moving often and well, paired with recovery and rest
separating emotions from eating

… and more.

You should have a good idea about what the above means (and feel like you have the basics down) before diving into more advanced practices/tools like tracking and adjusting macronutrients, carb and calorie cycling, chrononutrition (timing nutrition with carcadian rhythms), intermittent fasting and more.

If you skip the basics and dive right into a rigorous program, it might feel a little overwhelming and burn you out … quickly. It’s not the best strategy to go from zero to six days of workouts a week, rather than slowly and consistently building to twice, three and four times first.

The same goes for your nutrition!

In my opinion, IF can be a great tool for anyone who has a handle on basic nutrition practices and wants to experiment with different strategies to help fine tune a goal.

Intermittent fasting is *not* for anyone with limiting health conditions or a history of eating disorders, as it can lower your blood sugar and trigger past habits of restriction. It’s not for people who snack often or struggle with mood swings, irritability or focus without eating frequently (me!).

And finally, IF is probably not for you if you take medicine or have heavy physical demands in the windows of time you would need to be fasting in.

My Overall Thoughts and Coaching Advice

Intermittent fasting can be a beneficial dietary approach for many people, but it’s not necessarily suitable for everyone. Here are some factors to consider, which I have for myself and would walk through with a client before helping them in their own health journey.

I mentioned some of these points the the section above, but there’s more to think about.

Before deciding if intermittent fasting is the journey for you, consider your …

health conditions: Do you have health condition such as diabetes or a metabolic disorder? If so, you need to consult with a healthcare professional before starting intermittent fasting. Fasting may affect blood sugar levels and could potentially cause certain health issues to worsen.
nutritional needs: Are you a women who is pregnant or breastfeeding? Are you underweight or someone who has higher nutritional requirements like a child or teenager? It’s essential for people in these categories to ensure they’re meeting their nutritional needs adequately, so fasting may be a challenge and not ideal.
preference and lifestyle: Would you find it hard to stick to a fasting schedule due to your work demands, social commitments and personal preferences in regards to meal timing? What do you see yourself doing on vacations or when you have busier weeks or visitors in town? IF may not fit into everyone’s lifestyle and preferences, so make sure to take a look at the big picture.
psychological factors: Fasting can have psychological effects, such as increased focus or mental clarity for some individuals, but it may also lead to irritability, mood swings, or obsessive thoughts about food for others. It’s essential to consider your emotional relationship with food before starting intermittent fasting.
eating disorders: If you have a history of eating disorders, please approach intermittent fasting with caution as it may trigger unhealthy behaviors or attitudes toward food and your body image.
medication and supplements: Some medications and supplements may need to be taken with food, so this makes intermittent fasting less feasible for those who rely on regular treatments.
physical activity levels: If you’re someone who likes high-intensity exercise or has a physically demanding job, you may find it challenging to maintain energy levels during fasting periods.

So here’s the big question — do I personally practice intermittent fasting?

No, and I probably won’t for a long, long time … for several reasons.

The biggest ones on my list include preference (I don’t want to!), I like to eat *mostly* the same on vacations as I do at home and during busy/fun seasons, and the timing would make me feel like I’m missing out.

I preach the on the concept of “if you can’t maintain the diet you’re on for more than two months, it shouldn’t be your diet,” and I don’t see myself being able to fast regularly and enjoy the same quality of life that I have today. I’m a big snacker, and fully believe that WHAT you’re eating is way more important then WHEN you’re eating it.

I’m someone who has a small snack with coffee before breakfast to help with the absorption of caffeine into the bloodstream. I also snack often because I become quickly irritable or moody if I’m really hungry. (She gets HANGRY, y’all.) I get headaches and light headed when I feel my blood sugar dropping, or if I’m awake and it’s been several hours without a decent meal or snack. I also can’t sleep if I’m hungry. Throw a recovered restrictive eater into the mix and it’s just too many red flags for me. The cons severely outweigh the pros, but please keep in mind that this is what I believe to be true for me and my own health journey.

Some people prefer to skip breakfast all together … but this is not me. It might be my favorite meal of the day, and I always, always have it — even if it’s grabbing a protein bar and a banana on my way out the door.

I believe that the body naturally fasts overnight for (typically) ten or more hours. In some cases, I can see benefits from choosing a time to stop eating after dinner that works for you … so you could say that a lot of people naturally fast for twelve hours (example 7 p.m. to 7 a.m.), whether they realize it or not.

For this reason, I don’t typically recommend intermittent fasting to clients, but if it’s something they are really interested in pursuing, I go over the checklist mentioned above and walk through their own pros and cons. If they have a general understanding on nutrition fundamentals and seem like they’re in a good spot to experiment with nutrient timing, we can try different things and hope to find the sweet spot they can stick to long-term!

When it comes to fasting, there’s no right or wrong answer for everyone as everyone is completely different and will get entirely different results.

My biggest takeaway from this post is to encourage you to consult a medical professional and explore the best route for YOU that you can feel good about and keep up with, especially if you have any underlying health conditions or concerns.

heather - life in leggings - intermittent fasting advice

Fast too intensely or for too long and you might end up worse than when you started.

Start small, with baby steps and fasting periods, and you might experience a wide range of benefits that could include improved fat loss and better health.

Only you know what’s best for you!

Now I’d love to hear from you …

Have you ever tried intermittent fasting?
If so, what was your IF schedule and how long did you do it?
And are you still doing it today?
Results?

Thanks for reading!

xo, Heather