Intermittent fasting has gotten a lot of attention over the past few years and for good reason. The proponents of fasting offer all sorts of benefits: weight loss, decrease in body fat, longer lifespan, longer health span, increase will power, improved brain function, etc.
I wanted to give it a try and test out the benefits, so I started intermittent fasting and have been doing it for 2 years. I have found the purported benefits to be true and I’m so glad I gave it a try. It’s been so great that I’ve stuck with it and plan to keep going.
There are several popular ways to do intermittent fasting, also known as time-restricted eating (TRE), which is probably a more accurate way to describe it (the former restricts food and the later restricts time). The one I chose was the 16-8 protocol, which means you don’t eat for 16 hours of the day and restrict all your eating between any consecutive 8 hours of the day you want. During that time you can eat whatever you want. I basically means I don’t eat breakfast or a late night snack.
I still eat very healthy, restricting processed foods and sugar and only eat actual food. Most of what we find in the grocery stores in the U.S. I don’t consider actual food because it’s been so highly processed.
Other protocols recommend fasting for 3-5 days with only water every few months or some variation of the two methods described above. I chose to the 16-8 for practicality and the benefits I’ll describe below.
What does the science say?
Time-restricted eating has been shown in studies to help with weight loss, reduce fat mass, improve heart function, and enhance aerobic capacity, without changing your diet. You can eat the same foods and quantity of food and still get benefits by restricting “when” you eat! 1 That’s amazing! Of course, if you can improve what you eat as well, then all the better! If you’re looking to improve your outcomes by changing your habits, it’s easiest to start with one habit and build upon it, so shortening your eating window may be a good place to start.
A recent study showed that eating within a 6 hour window reduced appetite consumption and increased metabolism, often resulting in weight loss, even if a person eats the same number of calories each day. 2
How it benefits our bodies seems to be related to our circadian rhythms and autophagy, among other things. The circadian rhythm is affected as we age, when our sleep schedules are disrupted and by what we eat. This affects our metabolism and how we age. So those late nights partying or night shifts are actually bad for your health, but sleep is a totally separate topic worthy of discussion.
Restricting when you eat has been shown to be beneficial to your circadian rhythm in that a change in circadian rhythm affects gene expression involved in metabolism and TRE can reset your clock, which improves your metabolism.3
What are my results?
The most unexpected benefit of TRE has been the simplicity. I don’t have to think about what I’m eating for breakfast and I don’t have to cook it. I wake up and get on with my day without the time and energy needed to prepare and eat breakfast. That may sound like a small, trivial thing, but if you’ve got a lot of other things going on in the morning, from getting kids out the door to your morning routine of meditation and working out, that extra time and energy is nice. On top of that, decision fatigue is a real thing. Even small decisions take energy and that energy exertion adds up by the end of the day. As a minimalist, anything I can do to simplify my life while increasing my enjoyment and output is a good thing.
Knowing that I’m only eating during a certain time window, not only simplifies my day, but it gives me a sense of willpower and a daily chance to exercise it. I no longer feel like I have to take food with me everywhere I go in case I get stuck on the freeway or in a meeting and can’t eat. I feel free from ever being “hangry” or using a small amount of hunger as an excuse for anything.
Over time is has become a habit, so the discipline is less important because it’s now easy and doesn’t take as much willpower. The stronger the habit, the less discipline required.
However, the discipline still gets challenged when the whole family is eating an amazing breakfast that my wife cooked. Occasionally I give in since I don’t fast every day, just most days. I’ve allowed myself some flexibility.
Belly fat burn
I’ve worked out nearly every day of my life, as long as I’m not injured. I enjoy it but it also became a life long habit a long time ago. However, no matter how much I worked out and ate healthy, I couldn’t lose my belly fat. The belly fat that starts in a man’s late 20’s and gradually turns his body into a dad bod.
In 2002 I completed the Ironman Triathlon. One of the peculiar takeaways from that experience was how many people I trained and ran with had a high amount of body fat. My friend Kirk put it in perspective after he completed a year of running or walking every day when he said, “you can’t outrun your diet.”
Shortly after starting TRE I saw my belly fat disappear. It was nice seeing my abs again. The only way that happened was for me to eat less food and more importantly, allow my body time to process and reset each day by eating in a shorter window. As the research has shown, the time window may be more important that what we eat.
How does that happen?
During fasting times where a person doesn’t eat for at least 12 hours, the body takes time to clean itself out through a process called Autophagy (meaning self-eating). If we’re alway eating, then this doesn’t occur. It starts at about 12 hours of not eating so if you fast for 16 hours, you give your body 4 hours to clean things up.
Not only does this help with fat loss, it helps with longevity and is being researched for its ability to suppress cancerous tumor growth. TRE is a promising method of cancer treatment that could be used to enhance the efficacy of other treatments. It works by clearing damaged organelles and misfolded proteins to ensure cellular homeostasis.4
In addition, it’s been shown to provide improved brain function or as one research paper put it: “Our data lead us to speculate that sporadic fasting might represent a simple, safe and inexpensive means to promote this potentially therapeutic neuronal response.” 5
There are a few drawbacks aside from watching your family eat homemade pancakes with out you on Sunday morning. Sometimes I feel weak or light-headed, especially after a big workout, so I don’t fast on big workout days. I started out small by only fasting 12 hours a couple of days a week and then built up to 16 hours on 5-6 days a week and my body has adjusted. There’s been recent evidence that suggests fasting every day has diminished marginal benefits as your body adjusts, so I mix it up by taking a couple of days off here and there.
So I’ve seen a lot of great benefits from fasting and after reading some of the research, I’m sure there are benefits by body is experiencing that I’m not seeing. If you’d like to read more of the research, I’ve summarized some of it below.
Rhonda Patrick’s website and 3 appearances of the Joe Rogan podcast are great resources for not only time-restricted eating, but many other health promoting activities. Here are some of my takeaways from her articles:6
Here’s a great video of Dr. Patrick and Dr. Attia discussing TRE with Joe Rogan.
Benefits: studies show a decrease in circulating insulin, decrease in blood pressure (comparable to taking anti-hypertensive medications) and weight loss.
Obese participants in a study found after 4 days their levels of ghrelin, an appetite-stimulating hormone, to be reduced. Meaning, because they eat within a 4 hour window, counterinuitively, they felt more full than someone who ate within a 12 hour window.
Longevity: gene expression changed from TRE. The “levels of an autophagy-related gene increased by 22 percent, suggesting that some degree of autophagy occurred during the fasting window, and levels of SIRT1, an aging gene, increased by as much as 13 percent.” 7
In muscle, TRE has been shown to increase lifespan by 11-14% alone. Meaning, no changes in diet or restriction in calories. What an amazing discovery that suggests just by eating at certain times you can potentially live longer and healthier. 8
Muscle mass: TRE “in healthy males resulted in a decrease in blood glucose, blood insulin, and fat mass, while maintaining muscle mass.”9. Women in a study found that their muscles grew and their skeletons didn’t atrophy. 10
If you’re interested in what more you can do to stay healthy, read about all my daily routines to be as healthy as possible:
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