NOTE: I've had many people tell me this article has motivated them to try fasting. Here's how to try it in the way that's most likely to ensure success.
It’s been 13 weeks since I wrote the in-depth post on my fasting experiment (read that first if you haven't already), which I originally only expected to try for 8 weeks. But the results have been so life changing that I’ve decided to continue doing it through at least the end of the year, and possibly indefinitely. Here’s what I’ve learned and experienced over the past couple of months, along with the pro-tips I recommend for others interested in trying it themselves, and answers to the questions I get most often.
The main thing I’ve learned in the past couple of months is that fasting is deeply misunderstood by people, including the reasons for doing it, the science and nutrition behind it, the actual experience of fasting, how it makes you feel, and how best to be supportive of someone in your life who’s giving it a try. Fasting just isn’t mainstream enough to make sense to people, and they often immediately respond with “I could never do that” (which is how I used to also feel before really diving into it).
From my fasting experience I’ve also become convinced that the obesity epidemic in America can be solved by integrating fasting elements into our culture. I don’t know if fasting will ever reach that level of cultural prominance, but I do now know with certainty that there’s a solution out there that works, and although fasting is a very individual thing, I’m convinced that it could be codified into an approach that could work for anyone. This also means that if you are unhappy with your current level of health, fasting is something you can do to fix it. It may not be the only thing you can do, but from experience I can tell you that it is absolutely an approach that will work. If you’re serious about trying to become healthy, fasting will work.
Pic at left is from earlier this year, before I started fasting. Pic at right is from a recent trip to Hawaii (thanks Amanda for the acrobatics, and Sarah for snapping the action shot!)
Here are my results from the past 3 months: The most obvious change is in my physique: I’ve gone from 245.8 lbs, which is a weight I’ve been at for the past 7 years, down to 209 lbs, a reduction of 15%. My body fat has decreased from 33.7% to 26.3%, a reduction of 7.4%, and my Body Mass Index has dropped below 30 for the first time in as long as I can remember. My muscle mass has improved from 32% to 36.1% (more on that later). I’ve dropped from XL to L shirts, and even put a medium sized shirt on at the beach the other day, which I never thought I’d do. My waist has dropped 4 belt buckle sizes, from a 38 to a 34, which has meant that I’ve had to donate most of my old clothes. But even more importantly, I feel great — sharper mentally and with more energy overall. I did a baseline series of blood tests when I started this fasting experiment, but I haven’t yet run the “after” set of metabolic panel blood tests, as I want to reach my goal first, which is to get my body fat below 20%. In July I dropped 2.8% body fat, then 2.3% in August, 1.2% in September and 1.1% so far in October. If I can keep a pace of about 1% body fat reduction monthly, I should be able to hit that goal by April 2016, and I’ll run the “after” blood tests then, along with an blog post update.
Although the changes to my physique are the most obvious ones, and the ones that everyone comments on (with people literally saying they don’t recognize me from older photos), those are the secondary benefits of fasting, and they pale in comparison to what I believe are its true benefits, which is that fasting promotes a healthier body that can repair its cells more efficiently, lower the risk of diabetes, lower the risk of coronary artery disease, better regulate blood glucose levels, fight off cancers more effectively, stay mentally sharp longer into old age, and possibly even extend lifespan. This is what makes fasting so misunderstood. People think it’s a diet, because that’s what they see. But I believe it goes much deeper than that. I believe fasting enables my body to perform better, for longer; maybe even decades longer. And few things are more meaningful than having an opportunity to craft a body that lasts longer and serves you better into old age, so you can do more of the things you want to do, with those you love, for longer.
A side note: If you don't know the important stats of your own body, like your BMI, body fat percentage, HDL, LDL, triglyceride levels, etc, then before you really consider whether or not you should fast, you'll have to decide if you want to get serious about your health overall. If you don't know your baseline, you won't know how much you need to improve to get to an overall level of health that's ideal for you.
The science around fasting is still in its infancy, so deciding to fast for reasons other than the immediate health benefits (which alone are tremendous) requires one to make some decisions today about what you want your life to be like several decades from now, and some of those decisions aren’t yet fully backed up by large-scale, randomized, controlled clinical trials, although the early science on smaller mammals and some human studies is promising and fascinating. Here are a few quotes to illustrate what I mean (with a bunch more in my original blog post, if you want to dig deeper):
As I read articles like those, coupled with my experience over the past three months, I quickly went from “I could never do that” to “how could I not do it?” The data is strong enough for me to be willing to make a long-term bet on the health benefits of fasting, and even if they don’t pan out, it’ll still have very much been worth it for the immediate benefits in my physique and energy levels. Here are some of the common questions I’ve gotten from people who are curious about what it’s like to fast:
“How hard is it?” This is probably the one I get the most often, and the answer is a bit nuanced. Fasting the way I choose to do it isn’t easy, and I’ve watched some people around me not be able to stick to it. They just get too hungry. But I’ve also built up to a pretty intense version of fasting over the past three months, which I describe below. There are milder forms of fasting that one can start with, and I highly recommend starting with something sustainable for you as you learn the limits of your mind and body. Here are various options, from what I consider easier to harder:
“What kind of fasting do you do?” I’ll fast for two or three non-consecutive days per week, with each fast day comprising a 30 to 36 hour period without food. An example would be that I eat dinner on Sunday night, then have nothing except water, coffee or tea on Monday, and I don’t eat again until breakfast on Tuesday. Depending on the week, I’ll either do that one more time (say, on Thursday or Friday) or I'll do it two more times (say, on Wednesday and Friday) later in the week. I try to plan my fast days based on how much I know I’ll be eating on other days. For example, I was just on vacation in Hawaii for the week and knew I’d be eating well there, so for the two weeks leading up to Hawaii, I fasted three days each week instead of my usual two. Then, I fasted on the day I traveled to Hawaii, as well as the day I traveled back from Hawaii, which meant that I was able to fast just one day while actually in Hawaii. I found this to be a good balance between indulgence and fasting.
“Do you eat more on your non-fasting days?” For me, fasting has been an incredibly liberating experience, as I wrote in my initial post, because it’s the very first time I’ve ever felt like I’m in control of my body. I’ve always had a really hard time not eating when food is in front of me, even joking that food ‘talks’ to me — or at least, that’s how it feels. Fasting removes all of that difficulty: There are days when I eat, and days when I don’t. On the days I eat, I don’t try to control myself like I used to, which means that I definitely eat more than when I was constantly battling myself. But over the course of the week, my overall calorie count is still greatly reduced. For example, I used to eat 2,500 calories per day, seven days per week, for a total of 17,500 calories in a week. There’s science showing that people who fast eat about 115% of their normal intake on non-fasting days, which feels about right to me. That means that in 5:2 fast weeks, I’m ingesting 2,875 calories per day, five days per week, which still creates an overall deficit of 3,125 calories in a week (and in weeks when I fast 3 days, a deficit of 6,000 calories each week). So fasting gives me the ability to not need to battle my food consumption desires on my eating days, which is incredibly liberating.
“How does nutrition play into fasting?” Our family prioritizes fresh, organic, and less processed foods (i.e., the foods you’ll find around the edges of the grocery store, not in the middle aisles). I limit all types of sugars (fructose, table sugar, honey, agave, etc) by not adding them to anything I eat (i.e., I don’t add sugar to coffee) and I also treat carbs (bread, pasta, beer, etc) as indulgence vs. everyday items. You can think about fasting and nutrition as separate but related: You don’t have to change your nutritional habits in order to begin fasting, although by fasting you’ll likely become more aware of nutrition generally. The more hardcore you are with nutrition, the more effective fasting will be.
“Aren’t you starving all day?” Surprisingly, no. On fasting days I’m hungriest between lunchtime and late afternoon for about five hours. By dinnertime, I’m not very hungry and by the next morning, I’m not at all hungry. If you can get through the part of the day when you are hungry, it’ll go away. Not being hungry in the evenings is what allowed me to drop the evening meal on my fast days.
“Do you exercise when you fast?” Yes! Exercise has played a key part in my fasting. As I wrote in my original post, fasting is a part of a larger goal I have to get back into the kind of shape I was in when I was younger. I primarily do two things: CrossFit 3x per week for strength, and indoor rowing 4x to 6x per week for endurance and general fitness. Interestingly, I’ve found that if I do CrossFit the day after a fast day (say I fast on a Tuesday, and then have CrossFit on a Wednesday morning) I’m noticeably weaker. Fasting keeps me from hitting personal records around max weight movements as quickly as I was before I started fasting. However, I’m also getting leaner, which helps me improve in other CrossFit workouts that aren’t just about lifting max weight, and as a percentage of my weight, my muscle mass has increased, so not hitting PRs as regularly is a trade-off I’m happy to make. In contrast, I find that my rowing often improves on fast days, which was completely unexpected. If I fast on a Tuesday and row that night after fasting all day, I find that I can often hit a rowing PR. There’s something about having already exhausted the glucose in my body earlier in the day, and rowing with energy my body is getting from fat stores that makes for a longer, more even power output. It was really a surprise. So I’ve found fasting to be bad for pure strength output but great for endurance output.
“Will you fast forever?” Possibly. All I know right now is that I’ve found something that gives me control over my body in a way I’ve never otherwise had. I expect that once I hit my goal of getting my body fat below 20%, I’ll likely switch between 6:1 and 5:2 fasts, meaning on some weeks I might only fast one day per week, and on other weeks (say when I know I’m going out to a big dinner that week) I’ll fast two days. What I do know for sure is that I’m happily extending my eight week test through at least the end of the year, and likely through mid next year so I can reach my goal.
“What’s the best day of week to fast?” I’ve found weekdays, when my mind is on work, are much better than weekends. I’ll only fast weekdays with one exception: When I’m traveling, I’ll fast on a travel day, which is often a weekend day, because eating while traveling is usually a pain anyway since it’s hard to find healthy airport food. I’ve found that traveling West, while generally easier, is harder from a fasting perspective since the day is longer than when traveling East.
If you'd like to give fasting a shot, I highly recommend starting with the hour-long BBC documentary embedded in my original post. I've also been reading a free PDF e-book written by Dr. John Berardi, a nutrition expert, who tried various types of fasting and wrote a detailed review. But most of all, I encourage you to post your questions and comments below. I'd love to know what kind of impact fasting has in your life!
Daniel, love the blog post. It gave me all the ammo I needed to hit my target (and more) of 25 pounds of loss in three months. I went with the 5:2 fasting (tried to do Tue and Thu, but flexed based on events, travel, etc…). During the fast days, I stuck to black coffee and lots of water (i.e. zero calories) for 36 hours. During the feeding days, I ate only high reward foods (and smaller portions). I lost about one pound a week. After 30 days, I hit a wall, so I added StrongLifts 5x5 strength training every other day (love the free weights). My goal for next two months is to get stronger and loose another 10 pounds. Then, I will go in maintenance mode. I am a minimalist, so I continue to experiment with ways to simplify nutrition and exercise so it becomes a habit. Thanks.
Since I wrote this post, I've had a number of people tell me it's motivated them to give fasting a try. That's great to hear! If you're in that camp, here's how I recommend you go about it:
A buddy of mine asked if (and why) he should get IGF-1 tested as a baseline before he starts fasting. Here's my answer:
From this research paper:
"Prolonged fasting also lowered levels of IGF-1, a growth-factor hormone that Longo and others have linked to aging, tumor progression and cancer risk."
From this medical article:
"The hormone IGF-1 comes up a lot in your research; it seems to be a big factor in mediating the effects of calorie restriction and fasting. How big of a role do you think IGF-1 is playing overall in aging?
I think it’s a pretty big role, though it’s not the only thing that’s important. The reduction of IGF-1 is really key in the anti-aging effects of some of the interventions. Both the dietary ones and the genetic ones. We’ve been putting a lot of work into mutations of the growth hormone receptor that are well established now to release IGF-1 and also cause a record life span extension in mice. So we know for example with chemotherapy resistance if you fast mice and inject IGF-1 you reverse a lot of the protective effects of fasting. So it’s important; it’s not the only factor, but it’s certainly one of the key ones."
From this BBC News article:
"Arguably, the most interesting changes were in the levels of a growth hormone known as IGF-1 (insulin-like growth factor). High levels of IGF-1, which is a protein produced by the liver, are believed significantly to increase the risks of colorectal, breast and prostate cancer. Low levels of IGF-1 reduce those risks.
"In animals studies we and others have shown this to be a growth factor that is very much associated with ageing and a variety of diseases, including cancer," says Longo.
Studies in mice have shown that an extreme diet, similar to the one I experienced, causes IGF-1 levels to drop and to stay down for a period after a return to normal eating.
My data showed exactly the same pattern."
My buddy Kirk asked on FB:
"eating dinner together is [something] my wife really values - any tips on how to fast but still participate in family dinner?"
Yes agreed, and it can be hard on others to eat around me when fasting -- much harder than it is for me (especially by dinnertime when I'm not very hungry). On fast days, what we've found works best is for me focus on feeding our toddler, or if she's already eaten, I take her to the park or do some other fun activity with her while the rest of the family eats.
Here's a great comment from my buddy Tom on FB that I wanted to add on this thread:
"So I remembered reading this article in the NYT about an island in Greece where people lived very long lives. At the same time I was reading up on fasting as well and couldn't help think this had to be connected. The one thing this article never connects is that in the Greek Orthodox faith most times they fast 1-2 times per week!!! It's very apparent there's something going on here! You've motivated me to start back up! Keep it up!"
I love that article, especially the passage about these Greek islanders' diet:
"She found that her subjects consumed about six times as many beans a day as Americans, ate fish twice a week and meat five times a month, drank on average two to three cups of coffee a day and took in about a quarter as much refined sugar — the elderly did not like soda. She also discovered they were consuming high levels of olive oil along with two to four glasses of wine a day."
Here's a body fat chart showing why I have a goal of getting under 20% body fat (at my age, that's the "ideal" range). The reason I care about body fat more than BMI is well illustrated in this quote from a WebMD article:
"[BMI] numbers were developed using data from enormous numbers of people. They don't tell you anything about your own body composition, how much of your weight is fat, and how much is muscles and tissue."
I'm turning 40 this December, and that's caused me to deeply re-evaluate my health. In high school I had wrestled at the 152 lb weight level and was a gymnast. In my 20s, I ran two 50 mile ultra-marathons and a half dozen marathons. I had a 33 inch waist and weighed 185 lbs. I could eat whatever I wanted and stay in good shape. But after a decade of doing startups, I found myself in my late 30s in much worse shape. My metabolism hit a wall when I turned 30, and although I didn't eat terribly, I also found it hard to figure out exactly how to get back to where I was in my 20s. My waist was 38 inches and I weighed 245 lbs; 93 lbs over my wrestling weight. My triglycerides were 33% above where they should've been. I'd imagine this happens to many of us as we get older, and I felt helpless as I watched all of this unfold, almost like it was happening according to some script that I wasn't in control of. Most of all, I was really disappointed in myself for not staying on top of my health, but I couldn't find the right balance of eating and exercising to change the path I was on. It felt like I was on a slow motion slippery slope as I got older and more out of shape.
When my daughter was born in 2013, I made myself a promise: I would be in as good of shape when I turned 40 as I was when I turned 30. I didn't want to have a hard time keeping up with her as she grew up. I started doing CrossFit twice a week that year. I signed up and completed a few triathlons. But my weight still wouldn't budge from 245 lbs, and my triglycerides, although lower, were still 15% above the max recommended range. CrossFit was making me much stronger, but that was only part of the puzzle. I had to figure out the rest, and I hadn't quite cracked it.
In December of last year, I realized I was running short on time: I'd really have to hump it to get back in shape within the next year, before my 40th birthday in December 2015. By this time I had upped my CrossFit schedule to 3x per week and I started rowing for 15 minutes before CrossFit started in the mornings. But that still wasn't enough: By April I knew I was going to have to take some much more drastic measures to reach my goal.
This blog is a story of those drastic measures, and how they're going. It's a deep-dive into the rabbit hole that we call 'health' as I see it. It's a journey that I invite you to take with me as we all get older, together. I am only starting to unlock some of the things that affect my body and I would love your thoughts and opinions as well in the comments below.
Let me also caveat this entire blog by saying that some of what I write about below is contrary to the things we've been told to believe, and I fully recognize that. I'm not a medical expert and I'm not telling you to throw away what you believe to be true. But just walk into all of this with an open mind, as I'm trying to do, and more importantly, be willing to try some of these things yourself if you also want to experiment a bit to try to find a better path than you've found so far.
Cheat days – The world’s most perfect answer to dieting. If you haven’t tried it yet, now is the time to give it a go. It’s easy.
The majestic power of the cheat day lies in how it addresses the food cravings you’ve been building up all week by following a strict diet.
Cheat days laugh in the face of cravings and ride off into the sunset with a smug smirk. That could be you, if only you knew how to implement cheat days for maximum effect.
Let’s face it – you like the binges, and you like the boosting effect it has on leptin and ghrelin, the two big boy hormones of fat loss.
But the day after the cheat day you feel something…odd. You took it too far, didn’t you? You ate too much. Way too much.