Intermittent fasting is a big trend today in the health and wellness world. If you haven’t heard of it yet, it’s only a matter of time. As someone who takes snacks with me everywhere I go and religiously eats before workouts, I was super skeptical at first. I thought it was a fad diet and just way too difficult to maintain. But after learning of the long list of benefits, I had to give it a try.
IF has been linked to increased life expectancy, immunity, energy, cognition and clear thinking, lower blood pressure, improved efficiency of the pancreas, weight loss, and even the ability to stave off neurodegenerative diseases. (1)
When you hear the word fasting it can be quite daunting. And don’t get me wrong, some forms of IF are definitely intense and involve major lifestyle changes. But other approaches to the diet can be quite manageable and easy to incorporate into your lifestyle. So first, let’s get clear on the different types of intermittent fasting.
The most popular fasting diets are 5:2, Alternate Day Fasting, and 16:8 (or sometimes 18:6). For the 5:2 Fasting Diet you fast for two days out of the week. That means zero caloric intake for 24 hours, twice a week with a normal eating schedule for the other 5 days of the week. For Alternate Day Fasting, you fast every other day. And for the 16:8 fasting diet, you fast for 16 out of 24 hours in the day and eat during an 8-hour window every day.
And by fasting, that means ZERO calories. Calorie free liquids like coffee and tea are allowed, but other than that (and of course, water) you’re not consuming any calories until you break your fast. Some people will say a bit of cream in your coffee is ok because it's a negligible amount of calories. But the jury is still out on whether even that is enough to break a fast, and I wouldn’t recommend any of my clients use cream in their coffee anyways (#switch4good)- so either go black coffee or tea or just stick with water.
The one thing to remember regardless of how long you decide to fast is that it’s not about extreme calorie restriction. You need to be sure to consume enough calories during your eating window so that your body doesn’t think you’re starving and start burning muscle or throw your hormones out of balance.
If your goal is weight-loss, it’s important to only decrease caloric intake by .20-.25% during your eating window each day. This will allow you to safely and responsibly lose 0.5 - 2lbs /week, without risking muscle loss or hormone imbalance.
For me, the 16:8 approach definitely felt the most appealing. I already aim to eat an early dinner each day, so adopting this diet really only meant pushing my breakfast back a few hours and avoiding my pre-workout snack. Plus, aside from sounding like pure torture, the longer fasting windows mentioned above do carry some risks.
Recent studies warn that fasting every other day can negatively affect how the body releases insulin over time, raising the risk of diabetes. (2) And for women, if done incorrectly, intermittent fasting can cause hormone imbalance and lead to infertility (3). The danger occurs for women when caloric needs during the eating window are not met, restricting overall caloric intake to an unhealthy level. Women are more sensitive to signals of starvation and more susceptible to feelings of insatiable hunger. This hunger can then lead to binging during the eating window, throwing off the hormone balance and has the potential to disrupt ovulation. The best way to avoid this is to keep the fasting windows smaller so that insatiable hunger is never experienced and binging is less likely, and by consuming enough calories during the eating windows.
Intermittent fasting for long periods of time can also exacerbate preexisting anorexia, bulimia and binge eating, so it is not recommended for anyone with a history of eating disorders.
For myself, the potential for hormone imbalance was a big red flag and definitely a risk I was not willing to take. But after doing some research I learned that it doesn’t mean IF is completely out of the question for me. While I do not intend to continue with IF once we start trying for a baby again or when we do get pregnant (definitely NOT recommended), if done correctly with short fasting periods, IF should not have any effect on future fertility.
The most effective window to fast appears to be 10 pm- 2 pm because most of the hormonal benefits like increased growth hormone secretion and better insulin management occur when you don’t eat in the morning. This window is simply not realistic for my schedule though, or anyone who has a day-job, or just prefers to work out in the morning. Ideally, you want to work out right before you break your fast- making your first meal a post work-out snack or lunch. If your fasting window is 10pm-2pm, this means getting a work out in around 12:30 or 1 pm. If you train in the morning like I do, stretching your first meal all the way to 2 pm can be tough after a work-out, and you miss out on that post work-out refuel. Also, eating my last meal at 10 pm doesn’t make any sense for my schedule when I have a toddler who eats dinner at 5 pm. I’d also prefer not to eat so close to bedtime, either. If your schedule allows you to train at midday and eat your first meal at 2 pm and last meal at 10 pm though, try it out. If it doesn't, simply adjust your eating window to a time that does work for your lifestyle.
6pm-10am Fasting Window
As I mentioned above, I chose to stick to my 5 pm dinner time, aiming to have my last bite at 6 pm each night, and fast for the next 16 hours until 10:00 am. Sometimes depending on the intensity of my morning workout, or just how hungry I was, I would break my fast earlier. But no matter what time I ate in the morning, I never consumed any calories after 6 pm. (Other than on a night out with friends, which is totally reasonable and highly encouraged)
Think of it as less of a diet, and more of an “Eating Schedule”
The average person eats food throughout the day for about 13 hours from 8 am- 9 pm, and then they fast for approximately 11 hours overnight. The true fasting state though, when all of the benefits of fasting occur, doesn’t technically begin until all the food of the last meal is digested and insulin levels have dropped. This means the average person actually spends about 6 or 7 hours in a truly fasted state each night. So, the goal of IF is to extend this fasting period and increase its many benefits, without slowing down the metabolism, throwing off the hormone balance, or losing muscle.
Since my goal with IF was not weight-loss, I aimed for the same number of calories I normally consume, just in a smaller window throughout the day. However, if your goal is weight-loss, decreasing the hours of the day in which you eat definitely makes it easier to consume fewer calories overall. IF, when done properly can be an excellent tool for weight-loss, especially those last few stubborn pounds.
Go slow and be kind to yourself
Before I started, I made a promise to myself to listen to my body each day and set the intention that if the feelings of hunger ever felt too intense, or my energy levels dropped- I would break my fast early and just try again the next day.
If 16 hours seems too challenging at first, you can also aim for a 14 or 15-hour window your first few days, and gradually increase to 16 hours.
I think this more forgiving approach, coupled with an understanding that the fasting period was not a time of punishment or restriction, but actually a time for regeneration- was what ultimately allowed me to do IF happily for three weeks.
My Results and Experience
After three weeks of IF, the number on the scale did not really change. However, my lean muscle mass did. I am a little more toned, and my body fat has very slightly decreased.
Aside from two occasions, over-all I did not feel tired during my fasted workouts. For yoga, Pilates and light cardio workouts, to my surprise I was totally fine working out in a fasted state. I didn’t have any less energy during the lighter and moderately intense workouts and I didn’t experience any insatiable hunger afterward, either. Going forward I plan to continue doing less intense workouts in a fasted state and break my fast with a small pre-workout snack on mornings when I know my workout will be high intensity.
Digestion and Sleep
The biggest benefit for me so far has been an improvement in my digestion and a decrease in bloating. Fasting allows your body the time it needs to digest properly before you start filling your belly again. Eating an earlier dinner and avoiding any food before bed is a big factor in this and for me, it also has also meant better sleep at night.
Less Dessert and Sweet Treats
“Closing the kitchen” at 6 pm also makes it a whole lot easier to avoid eating dessert in the evenings. I realized I actually don’t need that sweet treat after my meal every night. I surprised myself with how quickly the craving went away once I realized what time it was. Moral of the story- I totally survived without the sweet treat each night and committing to no food after 6 pm made it possible.
Instead of reaching for food first thing in the morning, extending my fast for a few more hours each day allowed me to focus on drinking more water. Before I took my first bite at 10:00 am, I was trying to drink at least 1 liter of water. Being more hydrated definitely contributed to the improvement in digestion and sleep I experienced too.
Having a set schedule to eat rather than grazing all day and snacking into the evening means I’ve been much more mindful when I do eat. Experiencing true hunger when fasting makes you really want to savor and enjoy your food during your eating window. I realized that I’d gotten into a habit of eating as soon as I woke up, whether I was truly hungry or not and sometimes before having any water. IF has helped me turn off the auto-pilot and really listen to my body to recognize real hunger cues. With IF there has been a lot less grabbing snacks on the go or eating meals standing over the kitchen sink and much more sitting down at the table and enjoying my meals mindfully.
Productivity and Concentration
Not only was I not dragging ass in my workouts in a fasted state, I also had much more energy to work in the mornings than I expected. I do most of my work in the office between 6 am and 7:30 am before Sebastian wakes up and 10 am and 12 pm while Sebastian is at preschool- with a workout somewhere in between. I was worried that I would be so hungry while fasting that it would be hard to focus, but I actually experienced the opposite. My head felt clear, I could concentrate with no problem, and I was more productive because I went straight to work in my office instead of fixing myself a huge breakfast that required a massive cleanup afterward.
If your afternoon is your most productive time of the day, this schedule might be tough as much of that time until dinner was spent preparing and eating food. It was definitely a schedule that works with my lifestyle but that may not be the case for everyone.
I’m really glad I tried this and I plan to continue to incorporate IF into my lifestyle going forward- with a few minor tweaks. In the future, my IF schedule will probably involve a 16:8 fast 4-5 days out of the week, and a 14:10 fast for 2 days when I do High-Intensity Interval training or lift heavier. However, I aim to continue “closing the kitchen” by 6 pm every day of the week no matter how long I fast and hopefully continue to enjoy the improved digestion and sleep that has afforded me.
If you’re interested in IF, give it a try! I was very skeptical at first, but it’s now become a part of my everyday routine. If you have a history of disordered eating, please consult with your physician or nutritionist before changing your eating habits.