A Nutritionist’s Perspective: Safe Fasting

In my last post, I laid out the many different versions of fasting, both intermittent and extended. This post, as promised, will address the minutiae, cautions, and contraindications for fasting overall.

Minutiae

What breaks a fast?

That’s going to be subjective, to an extent. Technically the consumption of anything breaks a fast. The word “fasting” is the literal abstention from the intake of anything, including water.

Now, would I EVER recommend dry fasting and the avoidance of water? Um, no.

Do I also count my fatty coffee and/or bone broth as still being in the fasted state? Yes. It’s called balance y’all.

Just kidding. What this means is I practice intermittent fasting on a daily basis, but consume fatty coffee and/or bone broths in the morning until I eat my first meal. I log all of this time away from actual food as my “fasting window,” even though I’m technically taking in liquid calories.

I determined this was a safe bet for me because firstly, it’s very low calorie, and second, I’ve tested my blood sugar and do not get a blood sugar spike from consuming either of those warm beverages in the morning. If blood sugar isn’t spiking, then insulin isn’t spiking, and my digestive system is still able to stay on its “break.”

Plus I notice a brain boost with those beverages — my cognitive performance is enhanced without causing extra stress on my body. Win-win for me. (Future post to come on the benefits of fasting, for the right people!)

Put simply: creamer, collagen, bone broth, etc. should all be fine to sustain your fasting window without breaking it, assuming there are no added sugars, high-carbohydrate ingredients, or tons of calories in them.

My example won’t be the best case scenario for everyone. On that note…

Tracking your blood sugar is a good idea.

Fasting isn’t a one-size-fits-all tool. Some people should NOT participate (keep reading to find out who). One way to know how you’re handling it, whether you have noticeable negative symptoms or not, is to check your blood sugar. In fact, all Americans could do well by having a glucometer in their medicine cabinet. Keeping a periodic eye on how your blood sugar is trending is such helpful data for determining how your food and lifestyle are suiting you.

I personally have one I bought from my local drugstore with a 100-pack of the corresponding brand’s test strips and alcohol wipes to clean the area before and after testing. I test when necessary and keep a little sheet of paper in the glucometer zip case to jot down the date, time, and blood sugar readings to keep track over time. This is particularly helpful if you are testing your post-prandial (post-meal) spikes in blood sugar to test how certain foods might affect you. I recommend this book for more details on this process. If you want to keep it simple, tracking blood sugar 30 minutes, 1 hour, and 2 hours after eating is a good way to see how you respond.

Get familiar with healthy blood sugar levels and processes such as gluconeogenesis.

It’s normal for blood sugar to dip a bit during fasting, but a healthy stress response will normalize levels through internal mechanisms like cortisol secretion and gluconeogenesis — which is the process by which your liver can produce glucose for stabilizing blood sugar from non-glucose sources, like the amino acids found in proteins or the glycerol found in fats. This is an amazing adaptive human tool by which our own bodies prevent our blood sugar levels from dipping too low (since that can be life-threatening, just as blood sugar being too high can be).

There’s also glycogenolysis, which is just the body’s breakdown of stored glycogen to use for fuel as glucose in the bloodstream as well. These processes can be turned on by the body during workouts, fasts, and low-carbohydrate eating patterns. 

Some folks in the health world warn about these things happening, but they are automatically kicking on whether you fast or not, so I recommend people get educated about them before jumping into a fasting regimen. It helps to know how things operate under the skin’s surface and get more acquainted with the miracle that is your human body!

If you want to talk more about healthy blood sugar regulation, let’s set up a time to talk.

What are the best ways to prep for a fasting practice? …and understanding hormesis.

I always recommend removing processed foods such as refined grains, added sugars, and industrial seed oils from one’s diet prior to engaging in bodily stressors such as fasting. Yes, it’s considered stressful, but (hopefully) in a good way.

Hormesis is the temporarily stressful or inflammatory result of bodily challenges that provide health benefits in the long-run. For example, lifting weights causes sore muscles. In the short-term, this is super annoying and difficult — you can barely move due to inflammation and tightness and it’s often painful, but over time as your muscle fibers heal and rebuild, they become stronger and make you more resilient to future stressors of the same kind (like heavier weight).

The same goes for fasting — temporarily, it challenges your internal blood sugar control and hormonal signals. In the long-term, it can stabilize insulin levels, shuttle out cellular waste buildup, and make you super efficient at utilizing the nutrients in your food.

So to safely and properly prep for a fasting practice, it’s best to remove the other hormetic stressors that could compound over time and be too much for your body to handle, because your body can only handle so much “hormesis” before it causes chronic stress issues — which would be doing the OPPOSITE of what we hope.

Some stressors to remove, avoid, or minimize prior to fasting include:

• Inflammatory foods, as I mentioned above (honestly this is one of the most important ones)

  • Instead: eat foods in their most whole/natural forms and drink tons of electrolyte water!

• Staying up too late at night or sleeping in too long in the morning

  • Instead: try to get a balanced 7-8 hours of sleep and go to bed around the same time, waking up around the same time, every night/morning.

• Drinking too much caffeine

  • Instead: try doing half caff (where half the grounds are from decaffeinated coffee, and yes they taste exactly the same) or using an adaptogen coffee mix!

• Working out too intensely (read on for more about this)

  • Instead: do more gentle forms of movement like yoga, walking, swimming, or lighter versions of weightlifting/cardio sessions you’d normally ramp up.

Cautions

Don’t push fasting if you’re hungry.

There’s a caveat to this — authors Mark Sisson and Brad Kearns have an awesome acronym that I like to use with my clients, called “WHEN.” To preface this, let’s start by remembering that it’s natural to have minor hunger pangs once in a while in-between meals. If it’s small enough, it’s likely that they are negligible, and you can continue fasting. The “WHEN” stands for “When Hunger Ensues Naturally,” meaning that once the hunger cues are strong and signaling to you that your body is expecting food shortly, it’s time to eat.

Do not force yourself past your body’s hunger signals simply because you’re trying to “keep a 16-hour fasting window.” No. Just no.

Like we’ve been discussing, the body has these signaling mechanisms in place for a reason. If you’re ravenous after ten hours of fasting, this is a reminder that your recent eating patterns are likely either too frequent, making it difficult to fast for too long (and therefore your body isn’t used to waiting very long for food every few hours), or you may have had a carbohydrate-heavy meal recently that left your blood sugar situation a little dysregulated. So just eat. You can always fast longer another day when your patterns are more stable. Putting forced stress on an already-stressed body is a no-no.

Stop if you experience unpleasant symptoms.

If during your fast you experience any unpleasant symptoms, such as dizziness, lightheadedness, or nausea, just eat, regardless of what hour-marker you’re at. Symptoms like this indicate blood sugar imbalances and might be telling you that you’re just not ready for extended fasting windows just yet, just like above.

Working out is okay… but it depends.

You can definitely workout while practicing intermittent fasting, but like I discussed above, remember that any challenge you put your body through is considered a stressor. Lighter forms of activity are best, but make that call based upon how you feel. If you’ve been practicing intermittent fasting for a while, you can try to increase the duration or intensity of your movement and see how it plays out for you. Again, any unpleasant symptoms should signal to you that what you’re doing isn’t working for you right now.

I would suggest, if you workout and you’re still in a fasting window, to ensure that your biggest meal of the day comes first in your eating window. Don’t wait too long after working out to eat, but also don’t eat immediately afterward either — your body is still coming down from the excitement and kick-ass-ness of your workout and your digestive juices need you to be calmed down a bit before they will do their jobs properly. You want to make sure you actually digest and absorb your post-workout meal instead of having it just sit there like a rock, making you wonder what you did wrong.

Otherwise, it’s probably best to perform your working during your eating window, to ensure you had plenty of fuel before you began and plenty of time after you’re done moving to settle in and get a nutrient-dense post-workout meal in before the night is over. Just my two cents.

The best way to break a fast is to start low and slow.

When your fasting period is ending and you’re ready to eat, my suggestion is to begin with something small, like a handful of nuts, a piece of fruit, or a small serving of protein (a couple eggs, quality jerky, etc.). Beginning with small portions helps get you digestive system back online, primed, and ready to begin breaking down food. Throwing too much food at an empty system too fast could lead to indigestion and malabsorption of nutrients.

Mind your salt needs — seriously.

Hydration and electrolyte intake are extremely important during fasting of any kind.

Fasting means not eating. Not eating keeps blood sugar lower. Lower blood sugar requires less insulin. Less insulin triggers the kidneys to excrete sodium faster than it normally would if you were eating. This is a natural process called natriuresis, and is normal.

But, because this occurs, your sodium (and other electrolyte) requirements go up. Unless otherwise instructed by your physician, plan to add salt or electrolyte mixes to your water and take small sips frequently throughout your waking fasting window.

Additionally, when you begin eating again, it’s common to gain a little weight in the form of retained water. Supplementing with some sodium during your fasted time can help mitigate this effect and keep your osmotic balance in check.

Electrolyte supplementation is critical if you engage in high-intensity athletics of any kind. You sweat water and salt, and further deplete levels through fasting or eating in a low-carbohydrate pattern. (This is why companies like Gatorade advertise for electrolyte replacement in athletes — it provides energy, osmotic balance, and keeps you in a healthy range.) The reason commercial electrolyte drinks are no bueno is that they’re typically packed full of added sugars and even vegetable oils! WTF?

Your best bet is to make your own, with filtered water, quality sea salt or electrolyte mix, maybe a squeeze or two of lemon or a drop of lemon essential oil, etc. There’s plenty of combinations that can get you flavor AND nutrition.

If you’re interested in trying the mix linked above, contact me and I can send you some samples!

Assess your current stress load.

I know I’m a broken record at this point, but if you are under crazy amounts of stress right now in your life, adding fasting to the mix is not going to help you. In fact, it could actually hurt you — it can cause thyroid or other hormonal imbalances, weight gain, disrupted sleep, and diminished mental and physical performance. Be sure to have stress management techniques in place to handle what you’re already going through before trying to do too much and wrecking your progress. And on that note…

Make sure you eat enough during your eating window.

I can’t tell you how many people I see undereating calories who shouldn’t be (read: everyone). If you’re safely restricting your eating to a specific hour-window, PLEASE ensure you’re eating ALL the calories you need for the day during that time. Don’t try to eat less calories AND intermittently fast. That’s a recipe for hormonal disaster and I can’t emphasize enough how important it is to not be depriving your body of energy and nutrients. If you think you’re even remotely undereating, avoid fasting altogether for the time-being and seek help from a nutritionist to get you back on track.

Who Fasting Isn’t For

Pregnant or breastfeeding women

Women growing and/or feeding another human using an extension of their bodies is an absolute miracle and, as you could imagine, requires tons of calories to sustain TWO lives.

Fasting, even intermittently, in this population puts both mom and baby at risk for nutrient deficiencies due to caloric restriction, and can really disrupt the thyroid and HPA axis. Getting proper nutrient stores is the #1 goal of pregnancy and breastfeeding, and eating EXTRA food, often, is usually the best way to do so. Of course, this should primarily come from nutrient-dense foods to ensure this goal is met, but you get the overall idea.

Giving birth and sustaining life with one body is a physical stressor (oftentimes traumatic) on the body, and in order to repair and heal and go on with your healthy life, your body requires extra nutrition. Don’t deny it that!

Additionally, many upcoming and new moms may be affected with body image issues surrounding the ways their bodies change size and shape throughout pregnancy and post-partum. Fasting may be seen as a means to an end for weight loss or body size control, and that’s not a healthy idea, for anyone involved, as it could lead to body dysmorphia or eating disorders.

Young folks under the age of 18

This should be obvious, but most bodies under the age of 18 are still growing and require extra nutrition as well. Sure, it can be argued that our ancestors often went through periods of fasting that affected the entire tribe, young and old, but we’re in modern times now and there are enough stressors challenging our kids these days. Let them be kids, let them eat (healthfully), and get to a place of good nutritional status before they consider fasting.

People with pre-existing conditions that make fasting contraindicated

This includes people with prior or current eating disorders, where restricting food to specific times (even for healthy purposes) could be triggering for recurrence or worsening of their condition. Fasting isn’t worth it enough to risk this, ever. Whole-body health is way more important than this one tool — a tool which wouldn’t even be serving this person well, anyway.

This also includes people who have been medically advised to or given a prescription for specific eating patterns and times. Of course, always listen to your treating physicians first and foremost, and even run these ideas past them prior to taking part. Medical clearance for a tool like fasting is always a good idea.

And, of course, as mentioned above — the overly stressed and undereaters.

Now — I’m curious. Have you tried fasting? Was it a good idea for you at the time, or did you learn something about yourself in the process? Leave a comment below and tell me about your experience, how it might be the same or different than some of the ideas in this post. I’d love to hear from you!

Until next time!