The Question

What would happen if I do Intermittent Fasting for 30 days?

More specifically, what would happen if I did not consume anything with calories until around 11am each day. Essentially, I will skip breakfast and make lunch my first meal of the day.

For anyone looking for research on this topic, look up both the term “intermittent fasting” and “delayed eating.” Much of the literature refers to intermittent fasting in this vernacular because it more specifically and accurately represents what is happening. Animal studies will almost always refer to the practice as delayed eating.

Intermittent fasting can also be referred to as a window of eating. It is common to use an 8-hour window of eating, which means the person fasts for 16 hours. This would be denoted as 16:8. I held to about a nine hour window of feeding or 15:9.

Normally, I eat in a 14-hour window, with 10 hours fasted, so 10:14. There were a number of reasons I choose to hold to a 15:9, but the most important is that it felt approachable and sustainable based on my cravings and lifestyle.

For context, I normally eat breakfast. It is usually some variation of eggs, potatoes and bacon.

Therefore, the question I really tested went more like this…

What will happen when a Functional Fitness athlete who normally eats in 10:14 fasting to feeding window change to a 15:9 window?

Hypothesis (Day 1)

Completed on Day 1 of Intermittent Fasting.

I will experience a minor decrease in inflammation, especially around key joints. Food sensitives will be slightly decreased in the meal which broke the fast. I will lose 2-3 pounds over the course of the month. Certain days the eating window will be a relief, while other days it will be a stressor. Many of the differences I will notice will be around my mental and emotional relationship with food.

The Results (Day 30)

30 Days of Intermittent Fasting are completed.

I experienced a mild decrease in inflammation during this period. I believe this could have come about from eating an appropriate amount of food (versus overeating), not just the change in the eating window. Also, my total exercise volume has been reduced the last several months compared to prior training cycles, which I believe had a more significant impact than food volume or timing. Often increased exercise means increased food intake, so it is challenging to distinguish exactly which factor accounted for the change. I’m sure both did, but training volume to a greater extent. I have sensitivities to dairy and certain sugars common is processed foods. The dairy sensitivity did not improve in the meal that broke the fast as predicted. However, I did experience less GI distress during the month of intermittent fasting. Processing of sugars would certainly be included in this overall picture of digestive health. If you think of your intestines as a filter, which is essentially how absorption takes place, the less total volume that is being force through the filter the more fully and effectively it can do its job. This is a benefit of ceasing constant feeding, rather than intermittent fasting, as these are not the same thing. Every human should take breaks from feeding, but this does not have to be intermittent fasting. I lost between three and four pounds during the month. This was not the goal and this effect may not have happened for a different person. Likely this is where my weight set point is right now and my body balanced out to a sustainable middle ground. This change was almost entirely due to being in a caloric deficit rather than a surplus. This mild caloric deficit likely contributed to much of the benefits I observed throughout the month. Intentionally listening to my cravings meant eating only when I was hungry. To me this was a more important takeaway than waiting to eat or eating less because it is universal to everyone, including the chronic undereater. The first ten days of the month, I got to skip breakfast. The second period of ten days, I skipped breakfast. The last ten days, I chose to skip breakfast. In other words, my body and mind found relief in not forcing food in my face first thing in the morning that first week or so. The first several days, I did not get hungry until around 11am. The last ten days, I routinely woke up hungry. Again, the universal takeaway is listen to your body and your cravings.

If you are not hungry, do not eat. If you are hungry eat real food.

Just because it is 7am, 12pm or 6pm doesn’t mean it’s time to eat. Eat when your body tells you it needs food. To my surprise, I never felt like I was depriving myself during the month. There were times when I was hungry before my eating window, but I was okay with the degree of hunger and even comforted by my body’s ability to talk to me. I think in part, this level of comfortability was facilitated by a relaxed mindset. I did not set “rules” for myself and I did not force myself not to eat. This month was about removing a stressor (making breakfast every single day) not about added to my stressors. If I found breakfast enjoyable on a regular basis and waiting to eat took that experience away, I would not have had the same outcomes. I should note that I broke my feeding window twice. They were both occurred on a Saturday morning, in settings that meant breakfast contained a relationship / social aspect. I ate with my wife. I do not regret breaking the fasting window, I chose to do so. Maintaining healthy, positive relationships in your life is more important for health, happiness and performance than meal timing ever will be.

Want to learn how I optimize my nutrition for competition? Listen to Episode #007 of The Fitness Movement Podcast on CrossFit Competition Nutrition.

What I Learned: Takeaways

1) Nutrition, Politics & Religion

Honestly, I am always hesitant to make posts on nutrition. Food is like religion – in that – everyone has an opinion, and everyone thinks they are right. One person came off their diabetes medication by doing Keto and they swear by it for everyone. The Elite Functional Fitness athlete you follow on Instagram uses templated nutrition by Renaissance Periodization, so maybe you should try it. Your brother-in-law uses MyFitnessPal to track his macros, and he just ran his first marathon, so it must work for him. A dietitian on your latest podcast raved about the benefits of Paleo, and she have some good perspective considering she had been doing it since 2006.

Do not read this article and think that because something worked for me it will work for you. That is not why I write these articles. I attempt to pull out themes that are universal. Try not to filter the information you are reading to confirm what they already believe versus attempting to look at it as objectively as possible. As you do that, I’ll do my best to recognize where I have biases and in try to minimize them in the takeaways.

2) Food is Social

Most family gatherings, work parties and holidays all revolve around food. This is one of the reasons why people struggle to change their habits. For me, dinner is always a time to sit down with my wife and catch up on each other’s days and have meaningful conversation. I would never build in a habit of skipping dinner because that means that I’m losing valuable face time with my wife. My point is, there is nothing special about skipping breakfast besides the fact that it worked for me because it was not a social meal. If you eat breakfast with your spouse and children every day, I do not recommend skipping it.

A parallel example is of this is I have had countless people ask me, “Is it better to work out in the morning or evening?” I almost always reply with, “Whenever you will do it.” Adherence and consistency is optimal…not a time of day. If your mornings are filled with getting little ones out the door on time or prying your own eyes open, then a morning exercise routine probably isn’t sustainable. If you are a person whose day can snowball out of control by the answering to the needs of other people or putting out fires, you may be much more likely to skip your afternoon workout unless you get it in before the “world gets to you.”

If intermittent fasting causes you to get in more quality nutrition consistently by avoiding the processed foods you tend to eat for breakfast…try it out!

If intermittent fasting causes you to lose out quality nutrition that sets your day up for success on a number of levels…don’t do it!

3) Your Mind Matters

Food is one of the most basic human needs. People often react in irrational ways when their food supply gets threatened. [Note: it is only irrational for our current place in world history.] A stressed person will always under or overeat…I have yet to find anyone who is an exception.

Personally, I have historically overeaten when I am stressed. I get up as late as possible to maximize the time I sleep. I have worked to minimize these behaviors, but I’ve identified them as patterns. For me, removing the time and stress of having to get a full meal in first thing in the morning was a huge relief. It was a breath of fresh air not to feel as though I had to shovel the last bit of food into my face before I ran out the door. I think much of the benefit I received from Intermittent Fasting was from this reduced mental strain that manifested in a physical stress response.

4) Rituals Prior to Eating

Humans have always had rituals before eating a meal. After a hunt (sympathetic), food is prepared within the safety of the tribe (parasympathetic). Thanksgiving and reflection in the forms of song or prayer are common across populations and generations. The mind calms down and the body has a chance to see and smell the food and begin to prepare for systems for digestion.

After a lion makes a kill (sympathetic), it will pant until it can catch its breath (parasympathetic). Only then will it eat.

One side effects of the immediacy of twenty-first century life is everyone is busy and always on the go. Fast food is the problem. I’m not talking about McDonald’s or Arby’s…literally quick access to food and eating that food quickly is the problem. Humans do not digest in a sympathetic state.

If you aren’t pausing and taking time to relax and truly enjoy your food, and doing so with conversation and loved ones, then you aren’t making the most of your nutrition.

Any nutritional choice you make (whether intermittent fasting or otherwise) should be filtered through this truth.

Related: How Nervous System States Impact Nutrition

5) An Ode to the Overeater

Unfortunately, the people who most could benefit from intermittent fasting are also the least likely to do it. These are the people who are constantly feeding to maximize performance or constantly overeating in an attempt to gain weight and muscle mass. Based on cultural norms and idealized figures, this is often a male.

This was the camp I sat squarely in for a few years. For me, it was more about maximizing recovery and replenishing as much as possible for future workouts than about achieving a certain body size or shape. Once again, it comes back to the discussion of health versus performance. Again, the circles have some degree of intersection, but they will never overlap completely.

The person (the chronic overeater, who is trying to improve performance and muscle mass in the gym, who has other stressors and responsibilities in a busy life) is the person who could most benefit from intermittent fasting. Really, they would benefit from fasting in general, regardless of the type. Giving the body a break from the constant digestion, or lack thereof, will allow you to fully process the food you take in and extract nutrients (macro & micro) more effectively. Many organs associated with processing (e.g. liver, kidneys) will have a “reset” period and other factors (like insulin sensitivity) will improve.

Counter-intuitively, eating less for a period could allow your body to become responsive again and “systems may come back online” that allow you to increase muscle mass. This rebound effect isn’t guaranteed, but I can almost guarantee you will feel better in the process and you will be healthier.

6) An Ode to the Undereater

The demographic that is more likely to do a variation of intermittent fasting is also the group that should proceed with caution. This is the person who has chronically undereaten. For this person, eating less than other people has always been the norm. This person has either been afraid of gaining weight or has been in pursuit of weight loss for a long time. This person is often cold when other people are warm. Culturally, this is more women, but that is certainly not to say that certain categories of men don’t find themselves here.

The undereater in you likes the idea of skipping a meal. The reality is the benefits that I had from my 30 days in intermittent fasting, you will not have. The benefits I received were because my body took a break from stressed overeating in exchange for increase awareness of my craving and a more appropriate volume of food. If the chronic undereater began the same protocol they would likely experience increased cravings and be forced to ignore them. This takes your body further away from your instinctual needs, making it even harder for you to achieve what you want.

7) A Study of One

Take the changes I observed over the 30 Days with a grain of salt. They are unique to me. Remember, to take my athletic and nutrition history into account before considering if you will have similar outcomes. Also, the results a saw in the first 30 days would not be the same results for another 30. The biggest benefits I saw was in the first ten days of the experiment. I think the first week had as big of an impact as the subsequent three.

The change that made the difference for me was eating only when I was hungry and attempting my best to listen to the cravings of my body. That is the number one takeaway. Foster feeling.

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Related: What I Learned From Doing 15,000 Double Unders in 30 Days

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