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OK… OK… so, I have a confession to make; I didn’t actually “fast” for 30 days. I followed a pattern of Time Restricted Eating (TRE). The pattern was 16 hours of fasting followed by 8 hours of eating (16:8) also known as Intermittent Fasting (IF). More on this later.

Now that I’ve got your attention… and now that you know that I didn’t starve myself for 30 days LOL… here’s what I’ll be covering in this article.

First, I’m going to touch on the most common types of fasting. Next, I’ll discuss my 30 day experience with Time Restricted Eating/ Intermittent Fasting and what happened as a result. Finally, my short list of pros and cons to TRE/ IF (and why I would/ would not do it again). Keep in mind, much of this will be based on my experience and my opinion with fasting. This is not a scientific article.

A couple small points before we start; “fasting” does not always mean zero calories. Technically, a caloric intake below 25% of daily caloric need is considered fasting.

Second, there are many reasons WHY people choose to fast. They range from religious/ spiritual, medical/ therapeutic and diet/ weight management. I’m not going to get in to those here.

OK, now let’s go!

Types of Fasting:

  1. Alternate Day Fasting (ADF). With ADF, you fast for one full day. Then, the next day, you eat ad libitum (without counting calories or controlling intake). Then, the following day you fast again. Hence the name, Alternate Day Fasting.
  2. Another type of fasting is Whole Day Fasting (WDF). In this pattern of fasting, you’ll simply chose one or more days of the week to fast. Then, eat ad libitum in the other days of the week. The days chosen to fast do not have to be consecutive.
  3. In the third type of fasting, the pattern that I chose to follow for 30 days, is called Time Restricted Feeding (TRF). Also commonly referred to as Intermittent Fasting (IF).

As I mentioned before, TRE/ IF includes a period of fasting, which begins after your final meal of the day and then concludes with your first meal of the following day. The fasting window includes the hours while sleeping as well, so this makes it a bit easier.

There are several different patterns 12:12, 14:10 16:8, 20:4 and 23:1. The most common is 16 hours of fasting followed by an 8 hour feeding window. This is the pattern I followed.

My Time Restricted Eating/ Intermittent Fasting Experience:

My 16:8 fast began at 9pm and I did not consume anything with calories until 1pm the following day. I used an app called ZERO to time my fasts and send me a notification when it was time to begin my fast and when it was time to eat again. Believe it or not, this proved to be very helpful along the way.

Some of the fasting gurus say you should have nothing but water to be in a truly “fasted” state. But, I allowed myself water, black coffee or green tea in the mornings. At night, after 9pm, I would have nothing but water. Basically, nothing with calories while fasted. Also, I would workout in the mornings around 8am in a fasted state.

My concerns early on were; I usually like to munch late at night. So I thought getting through the evenings before bed would be the toughest. It turns out, that really wasn’t the case. And what I learned was, a lot of the late night munching was really just habit/behavioral. I wasn’t truly hungry.

On the other hand, the mornings seemed to be most difficult. I’m really a person that enjoys waking up and having breakfast. However, I just ended up eating breakfast at lunchtime LOL. What I learned however, was what “true” hunger felt like. Not ravenous hunger, but hunger. My body knew it was time to eat and my gas tanks on “E”. This, was a win because it allowed me the opportunity to become more perceptive/ in tune with being hungry (not just eating because I was bored).

Another interesting note, I feel like my stomach may have shrank slightly. A few days into the IF, I found that I was getting full much quicker. In other words, my body’s signal for feeling full would kick in much quicker and with a smaller meal than before IF; I was getting full on less food. If I were dieting, I would say that’s a pretty fair advantage.

Since I usually train somewhat fasted, I didn’t feel as though my workouts were heavily affected, albeit they were still affected. Before IF, I would wake up and have coffee with sugar free creamer. Then, shortly before my workout, a pre-workout supplement/ stimulant. For the most part, my strength was the same. Although, my cardio felt like it was affected negatively… just slightly.

So, I know you’re wondering now… “what happened to your body fat”?! I knew you’d want to know, so I kept meticulous record of what I ate through the process and had my Body composition tested before and after the 30 days.

First, it’s important to note, I’ve always maintained meticulous record of my food intake. I weigh and measure about 95% of what I eat and record it in the food tracking app, MyFitnessPal. So, I have a good baseline to start from. Second, I’ve established my “maintenance” caloric intake in doing this. And, for the sake of trying to eliminate variables, I chose to eat a maintenance calorie intake through the 30 day fast.

Second, I used the InBody machine to assess my weight and body composition before and after. If you’re not familiar, check the link. While all body composition tests have a degree of error, I decided to use the Inbody to remove any HUMAN error.

So, here are the details of the body composition testing.

  1. Starting weight/ BF% = 205.4/ 14.8%
  2. Ending weight/ BF% = 205.6/ 15%

While the test is far from scientific and only had an “n of 1” (me). We can see, while eating maintenance calories for 30 days and changing little to no variables, with the exception of TRE/ IF, I did not have any statistically significant change in weight or BF%. No real surprise there.

So, the takeaway message is; unless you are in a caloric deficit, don’t expect to lose weight/ body fat simply by following TRE/ IF. On the contrary, you may lose weight/ body fat while following TRE/ IF due to the unintentional caloric restriction from the limited time window to consume calories. Or, from the increased sensation of being full faster while eating as I mentioned earlier.

Pros and Cons to TRE/ IF. And, Would I do it again?: 

First the pros:

  1. I learned to pay attention to and observed what REAL hunger queues felt like
  2. My stomach felt like it shrank, or was getting full quicker while eating (might be beneficial if on restricted calories)
  3. Less eating occasions meant more time to focus on other things and less meal prep time

Now the cons:

  1. I had a slight reduction in my aerobic capacity. Strength wasn’t really affected, but my cardio felt like it took a small hit
  2. Feeling full might have been an advantage (if my goal was fat loss). But, since I was at maintenance calories, I was almost ALWAYS full. And, I found it hard to eat all my calories in the 8 hour window. Eating felt like a job… hahaha!
  3. I missed coffee with creamer and breakfast before 1pm… hahaha!

Would I do it again?

Short answer, yes! But, only if my goal were fat loss. Here’s why:

  1. Eating fewer times means larger meals. And, this (in my experience) seemed to trigger more satiety. During the feeding window, I was always full. So, this could be hugely beneficial while “dieting”.
  2. Because 2/3 of the day was spent either sleeping and/ or fasting, it might be easier to stick to reduced calories within 8 hours. My mind would be occupied with other things besides food which is also beneficial while “dieting”.
  3. I learned to differentiate between actual hunger and just boredom/ behavioral eating patterns.

What would I do different?

First, I would likely supplement with branched chain amino acids BCAAs during the fasting window. If you do the math, although not statistically significant, my body fat percentage slightly increased. This means there was a slight loss of lean mass (muscle). According to the Inbody, my skeletal muscle mass went from 101.4 to 100.8 (-0.6 lbs). Again, not significant and easily could be accounted for through the margin of error of the device.  I know taking BCAAs would mean I wasn’t truly “fasted”. However, I would still do so as a sort of “insurance policy” against muscle loss.

Second, I might change my training (or feeding window) to have my first meal immediately after my training session. Due to scheduling, this wasn’t convenient at the time. So, my training began around 8am and ended around 9ish. Since my first meal was at 1pm, this meant I went 4 hours after intense training before eating. This could have been part of the (negative) skeletal muscle mass changes. And, it also caused (in my opinion) more hunger than necessary.

Final Thoughts

I am glad I gave TRE/ IF an honest shake. I believe there are some benefits to TRE/ IF for those in a caloric deficit or looking to lose body fat. I don’t see much of a point in following this pattern while eating maintenance calories. Nor to I see there being any athletic performance benefit/ advantage.

Ultimately, TRE/ IF is another tool in the dieter’s tool box that may help make dieting seem easier by some hacks to the system of satiety. So, if your goal is body fat loss and you are cutting your calories, you might consider adding TRE/ IF to your arsenal.