What IS Intermittent Fasting?

Updated: Mar 25


There are many, many conflicting recommendations about what to eat, but not much focus is placed on when. As a trained nutrition professional, I even grew confused over all the current “studies”, and until recently, struggled with what nutrition recommendations to give my clients. Even more frustrating, a diet that worked well for one client, did not work well for the next. One felt great eating vegan while the next preferred keto. Some ate clean or paleo. Others excluded major food groups or all forms of sugars. Yet others felt good on a carnivore, or all meat diet. I scratched my head and researched all of these diets, trying to understand why some thrived on one while the next felt horrible following the same eating plan.


I heard about intermittent fasting on several podcasts I listened to. At first I disregarded it and rolled my eyes when I heard it referenced. Surely skipping breakfast and not eating all day was unhealthy! Every dietitian and nutrition professional knows this. However, I kept hearing the benefits broadcasted from professionals I had a lot of respect for, so I opened my mind and started doing my own research.


I dabbled in IF a little bit in early 2019, but I admit, if I got really hungry 14-15 hours into my fast, I would cave and eat. I have been eating breakfast almost immediately after rising every day my entire life, and everyone knows it is the most important meal of the day! I was one of those kids who ate a bowl of cereal or something similar as soon as I got up. As a child and teenager, I woke early and could never sleep late (this is a blessing and a curse). Even in college, after staying up into the wee hours of the morning, I could only sleep for a few hours after finally going to bed. Naturally, I have been eating breakfast early my entire existence.


In a nutshell, fasting is basically defined as any time you are not eating. If you finish lunch at 1 pm, you will digest that food for several hours. Your insulin is high, it’s not going to immediately drop the minute you stop eating. It will take about 2-3 hours, depending on how much and what types of food you have eaten.


Insulin starts to fall because you stored the food in the stomach for a while, and it then slowly gets partitioned out to the intestines. You’re still digesting food 3-4 hours after you eat. After about 3-4 hours, insulin starts to fall. It is then you start to get into a fasting state.

Gradually pushing back the time I typically ate breakfast in the morning worked well for me. It was challenging for me to jump right in and immediately fast 18-20 hours, because I typically wake between 5-6 am, and waiting until somewhere between 12-2 pm to break my fast seemed like an eternity. Some will agree that fasting and blood sugar control can be more challenging for women, as they do not have as much muscle mass or glycogen storage in the liver, as men. Female hormones also fluctuate daily.


Contrary to what we have been taught, it is not necessary to eat the moment we wake up. Our body naturally stimulates us as we wake. Each morning, counter-regulatory hormones (cortisol, epinephrine and adrenaline) are released. These signals tell your liver to make new glucose and wake you up. All these hormones release glucose into the blood for quick energy. This phenomenon is called the dawn effect. Our bodies are gearing up for action in the morning, not for eating. Morning hunger is a learned pattern that takes place over decades. There is no reason to refuel with donuts, sugary cereal and giant bagels as soon as you get up!


A good starting point is to not eat after dinner. This concept was easy for me because I had long eliminated evening snacking. Believe me, there had been many years of eating a little ice cream or a piece of fruit, or some popcorn before bed. I figured out I slept much better when I didn’t eat several hours before bed. I can’t tell you how many times I ate ice cream shortly before bed, only to wish I hadn’t because it always gave me a stomachache! Tip: the best way to avoid ice cream before bed is not to have it in your house. Ha!


Do not eat or drink any calories at least 3 hours before bed. Follow this guideline as much as possible.


If there is a day or two during the week that you really want to enjoy breakfast with someone or for a special occasion, do it! You can fast longer the next day, or shorten up your eating window and have an earlier lunch or dinner. This is a lifestyle and you need to make it work for you.


Some people do very well with one meal a day (OMAD). I practice this about once a week. It takes some getting used to, but it really simplifies your day! No breakfast preparation, no packing lunch, no cleaning up, less planning, and more money saved. I don’t see a downside! This is easier for me while I am away from home, as I don’t have access to my pantry. Practice this concept while at work as co-workers generally frown upon you stealing and eating their food.


Of course there are exceptions, but in general, the longer you fast, the greater the benefits, although I wouldn’t recommend fasting beyond 3-5 days without medical supervision. For those wanting support during extended fasts, you can work with me individually.

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