Life In the Fast Lane: My Experiment with Intermittent Fasting for Health and Fitness

UPDATE: I wrote this update 3 months after the original post below. Read below first, then read the update to get the latest!

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.

The Mind, or: My brain as my own worst enemy

I've often wondered if I have an eating disorder. I think I might. I've never had it properly diagnosed, but here's why I think so: When I look at food, it talks to me. I don't mean that it's literally speaking to me, but the feeling is that it's like a magnet and I feel this irresistible sense of attraction to it. It doesn't matter what kind of food it is, and it doesn't matter how hungry I am -- if there's food and it's out on a table, I want to eat it. I thought this was normal, and everyone felt this way, until five years into dating my now wife, I told her one day "isn't it crazy how food talks to you?" and she responded with "I don't know what you're talking about." And then I said to her (incredulously) "wait, are you saying that when you look at this delicious food, and then you look at something that's not food, like this glass, the feeling you get from those two things is exactly the same?" And she said, "that's exactly what I'm saying." That was a mind blowing moment for me. I had absolutely no idea that food didn't talk to other people. I have the hardest time not grazing on food that's accessible to me. I've talked to others about this since and I've come to the conclusion that people have this sense of irresistible attraction to food at varying levels. Some people say, for example, "yes I feel that a bit, but it doesn't cause me to pick food up and put it in my mouth." If you feel this a little, but you can control it, then just imagine that feeling but multiplied by 100x whenever you pass by any type of food. That's what it's like for me. And the worst part of having this feeling is that I get mad at myself when I eat the food, and yet I can't help myself from doing it. It's a really destructive thing, and I've literally never been able to control it.

Until I tried intermittent fasting. For the very first time in my life, I feel like I'm in control of my body.

I recently saw this BBC documentary that got me started with Intermittent Fasting. If you're interested in the topic, it's a really great place to start. I credit this documentary with helping me find an approach that puts me in control of my body for the first time.

I'm going deep on intermittent fasting in this first health blog installment because although it's just one of several things I'm doing to get in shape by December, it's the most effective and meaningful change I've made. In addition to fasting, I'm also rowing on an indoor rower 6x per week, and I'm going to CrossFit 3x per week. But here's the simple truth: Controlling the food you put into your mouth pays much greater dividends than trying to control how you burn the calories later.

It's not even close -- in our society today, with restaurant dinners that easily surpass 1,000 calories and scientifically engineered foods that trigger our primal savory + sweet cravings, it's hella easy to ingest way more calories than your body needs. If you only try one thing from this blog, my suggestion is that you try intermittent fasting.

First off, some vocab:

IF: Intermittent Fasting. IF means you fast for some period of time on a regular basis (and the time periods vary as you'll learn below.) Here's a guide to five types of intermittent fasting.

ADF: Alternate Day Fasting. Also called a "4:3 fast" because you are fasting every other day (i.e., on 3 out of every 4 days per week). This is one specific type of IF.

I'm two weeks into an eight week, 5:2 intermittent fasting experiment (where I fast for two non consecutive days each week), and although it's been the most meaningful thing I've done to date to lose weight, I'm not even doing it for the weight loss. That's just the great side benefit. I started doing it because of the amazing body of science that's starting to show how ridiculously good fasting is for one's overall health.

Although below I provide a summary of the benefits I've found in researching intermittent fasting (and some associated quotes), watching that BBC documentary above is the easiest way to get up to speed on the benefits of intermittent fasting.

"There is nothing else you can do to your body that is as powerful as fasting." - BBC Documentary

"Fasting alone is more powerful in preventing and reversing some diseases than drugs," said Satchidananda Panda, an associate professor of regulatory biology at the Salk Institute for Biological Studies in San Diego, California

" Data show that IF, when done properly, might help extend life, regulate blood glucose, control blood lipids, manage body weight, gain (or maintain) lean mass, and more."

Research on mice as far back as 1945 showed that calorie restriction in mice promotes up to 40% longer lifespans in rodents.

" Mattson thinks that intermittent fasting acts in part as a form of mild stress that continually revs up cellular defenses against molecular damage. For instance, occasional fasting increases the levels of “chaperone proteins,” which prevent the incorrect assembly of other molecules in the cell. Additionally, fasting mice have higher levels of brain-derived neurotrophic factor (BDNF), a protein that prevents stressed neurons from dying. Low levels of BDNF have been linked to everything from depression to Alzheimer's, although it is still unclear whether these findings reflect cause and effect. Fasting also ramps up autophagy, a kind of garbage-disposal system in cells that gets rid of damaged molecules, including ones that have been previously tied to Alzheimer's, Parkinson's and other neurological diseases."

"Restricting caloric intake to 60–70% of normal adult weight maintenance requirement prolongs lifespan 30–50% and confers near perfect health across a broad range of species. Every other day [ADF] feeding produces similar effects in rodents, and profound beneficial physiologic changes have been demonstrated in the absence of weight loss in ob/ob mice. Since May 2003 we have experimented with alternate day calorie restriction, one day consuming 20–50% of estimated daily caloric requirement and the next day ad lib eating, and have observed health benefits starting in as little as two weeks, in insulin resistance, asthma, seasonal allergies, infectious diseases of viral, bacterial and fungal origin (viral URI, recurrent bacterial tonsillitis, chronic sinusitis, periodontal disease), autoimmune disorder (rheumatoid arthritis), osteoarthritis, symptoms due to CNS inflammatory lesions (Tourette’s, Meniere’s) cardiac arrhythmias (PVCs, atrial fibrillation), menopause related hot flashes. We hypothesize that other many conditions would be delayed, prevented or improved, including Alzheimer’s, Parkinson’s, multiple sclerosis, brain injury due to thrombotic stroke atherosclerosis, NIDDM, congestive heart failure."

"The limited human evidence suggests higher HDL-cholesterol concentrations and lower triacylglycerol concentrations but no effect on blood pressure. In terms of cancer risk, there is no human evidence to date, yet animal studies found decreases in lymphoma incidence, longer survival after tumor inoculation, and lower rates of proliferation of several cell types. The findings in animals suggest that ADF may effectively modulate several risk factors, thereby preventing chronic disease, and that ADF may modulate disease risk to an extent similar to that of CR"

"A large body of evidence for the physiologic benefits and life-extending properties of CR now exists. Restricting daily energy intake by 15–40% has been shown in both animals and humans to improve glucose tolerance and insulin action, which indicates an enhancement in insulin sensitivity (7, 8); to reduce blood pressure and the heart rate, which is consistent with benefits for cardiovascular health (9-11); and to reduce oxidative damage to lipids, protein, and DNA, which implies a protective effect against oxidative stress (12-15). Many other effects of CR have been documented, including increased average and maximal life span (12), reduced incidence of spontaneous and induced cancers (13), resistance of neurons to degeneration (14), lower rates of kidney disease (15), and prolongation of reproductive function (16)."

Here are more specific benefits of intermittent fasting I've culled from my research:

The following are reduced:

Lowering triglyceride levels and improving other biomarkers of disease
Reducing oxidative stress: Fasting decreases the accumulation of oxidative radicals in the cell, and thereby prevents oxidative damage to cellular proteins, lipids, and nucleic acids associated with aging and disease
Alternate-day fasting may reduce body weight, LDL, and triglyceride levels to the same degree regardless of maintenance of low fat or high fat diet on the feeding day
Blood lipids (including decreased triglycerides and LDL cholesterol)
Blood pressure (perhaps through changes in sympathetic/parasympathetic activity)
Markers of inflammation (including CRP<, IL-6, TNF, BDNF, and more)
Oxidative stress (using markers of protein, lipid, and DNA damage)
Risk of cancer

The following are increased:

Cellular turnover and repair (called autophagocytosis)
Fat burning (increase in fatty acid oxidation later in the fast)
Growth hormone release later in the fast (hormonally mediated)
Metabolic rate later in the fast (stimulated by epinephrine and norepinephrine release)

The following are improved:

Fasting episodes trigger the process of autophagy [15] which breaks down and recycles dysfunctional proteins and organelles, and perhaps also the process of apoptosis which does the same with cells.
Intermittent fasting boosts production of a protein called brain-derived neurotrophic factor (BDNF), which activates brain stem cells to convert into new neurons, and triggers numerous other chemicals that promote neural health.
It also protects your brain cells from changes associated with Alzheimer’s and Parkinson’s disease. Research by Dr. Mark Mattson, a senior investigator for the National Institute on Aging, suggests that alternate-day fasting (restricting your meal on fasting days to about 600 calories), can boost BDNF by anywhere from 50 to 400 percent, depending on the brain region
Intermittent fasting helps reset your body to use fat as its primary fuel, and mounting evidence confirms that when your body becomes adapted to burning fat instead of sugar as its primary fuel, you dramatically reduce your risk of chronic disease
There's also plenty of research showing that fasting has a beneficial impact on longevity in animals. There are a number of mechanisms contributing to this effect. Normalizing insulin sensitivity is a major one, but fasting also inhibits the mTOR pathway, which plays an important part in driving the aging process.
Normalizing ghrelin levels, also known as "the hunger hormone"
Promoting human growth hormone (HGH) production: Research has shown fasting can raise HGH by as much as 1,300 percent in women, and 2,000 percent in men,2 which plays an important part in health, fitness, and slowing the aging process. HGH is also a fat-burning hormone, which helps explain why fasting is so effective for weight loss
Normalizing your insulin and leptin sensitivity, and boosting mitochondrial energy efficiency
Chronic fasting extends longevity, in part, by reprogramming metabolic and stress resistance pathways
Appetite control (perhaps through changes in PPY and ghrelin)
Blood sugar control (by lowering blood glucose and increasing insulin sensitivity)
Cardiovascular function (by offering protection against ischemic injury to the heart)
Neurogenesis and neuronal plasticity (by offering protection against neurotoxins)

I don't know if all of the benefits above are true. As I said, I'm not a doctor, and everywhere I researched, I kept seeing cautions that most of the real research done so far has been done on animals vs. humans. But I was intrigued enough to give it a try, so I went to my doctor 2 weeks ago and got a baseline of tests done: IGF-1, Hemoglobin, full metabolic panel. I'm going to try a 5:2 fast for eight weeks, and then get another set of blood tests done for a true before & after comparison. I'll also leave updates in the comments below on how things are progressing for me.

This 5:2 schedule allows for one small (600 calorie for men, 500 for women) meal on fasting days, which I've been doing in the first few weeks, but I'm going to try skipping that meal on my next fast day because by the evening of a fast day, I find that I'm not super hungry, as I mention in the video above.

The other thing I really like about 5:2 intermittent fasting so far is knowing that I can easily dial it back to 6:1 once I reach my target health goals, or I can ramp it up to 4:3 if I don't feel like I'm progressing enough. This is really what's helped me feel in control of my body for the first time: On fast days, I just say 'no' to all food. I don't have to fight individual cravings.

As this article mentions, we all practice intermittent fasting on a "12/12" basis already. We eat at regular intervals, typically between 8am-8pm, and then we don't eat between 8pm and 8am the next day (largely because we spend much of that time sleeping). The crazy thing about intermittent fasting is that it's not necessarily about restricting the overall calories you eat, but just about when you eat them. There's a lot of science that shows that you can eat the same number of overall calories in a week, but by fasting for several days per week, you still gain many of the benefits listed above. In reality, it's also likely you'll consume fewer total calories in a week if you restrict meals on 2 days, and in fact in the first two weeks of doing it I've dropped from 245 lbs to 230 lbs (the picture at top was of the scale the morning I wrote this blog!) which is a bit surprising. I'll be curious to see how that trend continues.

Exercising During Intermittent Fasting:

As this article mentions, "if you’re fairly sedentary during the fast, you may need the full 20-24 hours without food to realize the benefits. However, if you’re very active, or you exercise purposefully during the fasted state, you may be able to enjoy the same benefits after only 16-20 hours without food." I'm following a pretty robust exercise schedule, so I'll report on specifically how it is exercising during fasting. So far, it's been great -- here's a post I recently posted on Facebook:

That's quite a bit to take in to start! More to come, including more comments below. I'd love to hear what you think, and how it goes for you if you decide to give it a try.

Want to go deeper?

Experiments with Intermittent Fasting: A great blog by Dr. John Berardi on his very in-depth experiments with different approaches to intermittent fasting and the results he saw.
ScientificAmerican: How Intermittent Fasting Might Help You Live a Longer and Healthier Life
New York Times: 4 days, 11 pounds
The BBC documentary reporter, Dr. Michael Mosley, has gone on to create a website called "The 5:2 Fast Diet" and wrote a book about it, which you can find on Amazon. I haven't read the book so I can't vouch for it per-se, but it has 4.5 stars w/ 1600+ reviews, so I imagine it's a pretty good place to start if you want to dig in deeper. I'm also not a huge fan of calling fasting a "diet" because to me it's more about creating a healthier lifestyle with a very specific set of health benefits, but I suppose that putting the word "diet" in the title helps sell more copies.

Resources:

UPDATE:

Last week I dropped below 200lbs for the first time in 15 years, and I've shed 10.5% body fat, from 34.7% to 24.2%. Here's the output from my scale:

I got this question from a buddy: "am pretty intrigued and suspect I will try this. the 8:16 model seems pretty compelling place to start. Why didn't you start there?"

The 8:16 fast could be good for getting into a fasting lifestyle habit, but for me, I needed something way more drastic than 8:16 could provide. I was at almost 34% body fat when I started, with a goal to get under 20%. Doing 2 non consecutive day fasting has gotten me half way there in 3ish months. If anything, I may up it to 3 days of fasting per week until I hit my goal (also known as alternate day fasting; eat one day, fast the next and so on). I've been experimenting with that for the past 2 weeks; I will be writing a blog post update on all this soon.

What I've realized in doing this is that the first step to fasting is to set goals, or else it'll be like driving without a destination and wondering how fast you have to drive to get there. For me, my prioritized set of goals are: To be under 20% body fat, under 200lbs, with all my blood panel numbers in a normal range.

8:16 might be a good maintenance fast regimen after hitting goals. Although for me I'll probably just lower to one day per week and adjust as necessary to stay within my goal range.

My buddy Isaac just sent me this link of a relevant Quora post. Specifically, this answer absolutely describes my relationship to food (and the especially relevant part bolded by me).

The bolded part describes exactly why it's easier for me to fast for an entire day than to try to count calories, or eat smaller portions, or eat less food throughout the day.

"On the other hand. an 'unhealthy eater' brain works more like an addict brain. You need a higher amount to feel the same satisfaction, and sometimes your brain asks for more just a few minutes after. If you prohibit yourself, then is more difficult because we, as humans, HATE being told what not to do. So you become over aware of food. And when someone offers you something and you decline, oh man, don't dare to say that is because you can't. It is indeed a little annoying, especially if you cooked the dish yourself, or if it's your favorite. You want the other people to try it, dammit!. No diet will get in your way!.

So yeah. It's hard, because our brain is a d**k and eating is a very important social part of almost every culture. In my case, I've found that if I don't start eating it's easier for me than if I eat a little. It's kinda like pushing a boulder down a hill. It'S perfectly still alone, but if you push it, then there is no stoping. Most of my friends know that if I said no is (please) no, but in other situations I try to 'escape'. Sometimes I say I'm full, sometimes I say I'll try it later and sometimes I just accept the snack and put it back when no one is looking."

Here's an update from my 5th fasting day!

I'm going to write a separate blog about what I think to be true about overall healthful eating habits on ad lib eating days, but there's something that I'd love to get people's thoughts on as I put that blog together: In his book "Wheat Belly," Dr. William Davis makes the argument eating wheat is seriously detrimental to one's health, and has been a big cause of the obesity epidemic in America. He's not just talking about refined carbs -- he's talking about everything from white bread to whole wheat breads and everything in-between that has wheat in it. For example, did you know soy sauce has wheat in it? Now you do! Here's a list of many, many other foods from this blog that may contain wheat:

Bread and baked foods: All loaves, including pumpernickel, and rolls unless specifically stated; many "rye" and "corn" loaves contain some wheat; pitta, crumpets, muffins, tortillas, and tacos (should be corn but mostly wheat in UK), doughnuts, cakes, cookies, biscuits, crackers, croutons, packet snacks, rusks, waffles, pancakes, crepes, pizzas, pretzels, breadsticks, communion wafers, pasta, pastry, Yorkshire pudding, suet pudding, and many other puddings.

Cereals: Most cereals will contain some wheat. The exceptions are porridge oats, corn flakes, rice krispies and granola. However always read the label as some may still not be gluten free, especially due to cross contamination in the factory.

Flour and pasta: All of these will contain some wheat unless stated to be wheat free or buckwheat, which is not from the wheat family.

Meat and Fish: Burgers, rissoles, salami, sausages, corned beef, luncheon meat, liver-sausage, continental sausages, pates, meat and fish pastes and spreads, ham, fish and scotch eggs coated with breadcrumbs.

Vegetable products: Vegetable pates and spreads, vegetables coated in breadcrumbs, e.g. onion rings, vegetables tempura, tinned beans, (also tinned spaghetti, often grouped with vegetables), soups and tinned and packet snack or ready prepared foods.

Sauces and condiments: Gravy, packet and jar and bottled sauces, casserole and "ready-meal" mixes, stock cubes and granules, ready prepared and powdered mustard, stuffing, baking powder, monosodium glutamate, some spice mixes (check label).

Desserts: Most puddings, pastry, yogurts containing cereal, ice cream, pancakes, cheesecakes and others with a biscuit base.

Beverages: Malted milk, chocolate, Ovaltine and other powered drinks. Beer, ale, stout, larger, Pils lager

Confectionery: Liquorice, chocolate, chocolate bars and most wrapped bars. Other sweets (check labels).

Medication: Many prescribed and over the counter drugs contain wheat. Check with your pharmacist. Do not stop prescribed medication without discussing with your doctor.

Other: Glue on labels and postage stamps. Sometimes, a food label may not specify wheat but another form of wheat product:

Durum wheat, spelt (triticum spelta), kamut (triticum poloncium)
Couscous
Bran, wheat bran, wheat germ, wheat gluten
Farina
Rusk
Semolina, durum wheat semolina
Flour, wholewheat flour, wheat flour, wheat starch
Starch, modified starch, hydrolised starch, food starch, edible starch
Vegetable starch, vegetable gum, vegetable protein
Cereal filler, cereal binder, cereal protein.

I've only read parts of the book, but with almost 5,000 reviews and 4.5 stars it seems very well received. I'd love to know if people have any links to deeper scientific evidence about the dangers of wheat -- especially whole wheat. While white bread has a glycemic index of "10" (the highest), whole wheat bread isn't that much lower, at "9" according to this Livestrong article -- something this article also says is true. But I'd really like to dig a level deeper than other blogs on this topic and get to some baseline science.

Another friend posted this on FB:

First off, I totally know what you mean about food talking to you. I'm with you bud! Second, I once experienced the silencing of food -- I literally lost my sweet tooth COMPLETELY (for a period of time). It was right after I had been super sick with a stomach bug (C-Diff! It's truly horrendous) and after 4-5 days of barely being able to eat (voila! A kind of "fasting") I didn't find sweets tempting at all at food didn't talk to me anymore. So I get that there is something there.

BUT -- where does fasting end and a sort of eating disorder begin? Perhaps bc I'm a girl and we hear about the dangers of dieting/anorexia/obsessing over food more than boys do. But I gotta worry that people who already have issues will just call their eating disorder "fasting". Where is the line between it all? Food for thought (ha! Yes, intentional pun).

Glad to know I'm not the only one that has to deal with food talking to them :)

What's interesting about having done four fast days so far is that I've found myself reacting just a bit differently to food on my ad lib eating days. It's a strange new sensation and I'm not quite sure how real it is, but for example I fasted on Friday last week, and then yesterday, on Saturday, I had a few opportunities to pick food up that was just out on the counter and passed on them -- completely surprising myself in the process. I've read a lot about the science behind how fasting might change one's overall relationship to food (i.e., in the bullet points above I pulled out lines like "Normalizing ghrelin levels, also known as "the hunger hormone" and "Appetite control (perhaps through changes in PPY and ghrelin)" from the other blogs & literature, and I thinkwhat I experienced yesterday was proof of that for me personally.

It's too new for me to really say for sure, though, but it's an exciting prospect: I've always assumed that fasting would just make me hungrier on ad lib eating days, and make me want to eat more on those days. But I think it may be the opposite: I think that learning to get past hunger pangs on fasting days because I can't eat anything on those days might be helping me learn how to control my non-hunger-induced food cravings on other days. It's too soon to tell for sure but I'll definitely report back on that as I experience more of it.

RE: Where does a sort of eating disorder begin -- I can only speak to my own personal situation, but I really do believe that I do have an eating disorder, at least in the sense that I have never been able to control my food intake even though I've badly wanted to. So I suppose it's the opposite type of disorder to the one that you're probably referring to. At least in my situation, I've found fasting to be something that's allowed me to control that for the very first time. And specifically what I mean is that by not eating anything on fast days, I'm freeing myself to be able to eat and graze as I normally would on the other 5 days per week. Or to put it another way, having discipline 2 days per week frees me from having to have discipline 5 days per week, and that's a bargain that really works well for me. If there's something I want to eat on a fast day, I can tell myself "I'll just eat that tomorrow." The interesting thing is going to be, as I wrote above, seeing if I end up gorging myself on non-fast days, or if fasting does truly reset my relationship to food in a healthier way.

Beyond that, I'm sure there are people who shouldn't try fasting. I'd imagine this could be very bad for someone with an anorexia or bulimia nervosa disorder. Also it's not for children or pregnant women, someone with Type 1 diabetes (although interestingly I haven't read any literature about it being bad for Type 2 diabetics -- maybe because the health benefits directly counteract that type of diabetes).

Rene left this comment for me on FB; moving it here to expand on it:

"Thanks for sharing your story Daniel. A few years ago I found my myself 35 lbs overweight and finally decided to do something about it. I heard about the "8 Hour Diet", which I would characterize as "light fasting" compared to what you are doing. You only eat over an 8 hour period. In other words, you fast for 16 hours everyday. So, for example, if my last meal is at 7:00 pm then I will not eat again until 11 am the next day. I used this technique combined with push ups and an elliptical machine every day. I lost the 35 lbs in a little over a month. In theory you're supposed to be able to eat anything you want over those 8 hours and still lose weight, but I also watched what I ate. I would try to minimize carbs...although I didn't cut them out completely. Lots of protein....cheeses, nuts,steak, chicken, fish. Once a week I would allow myself a free day to eat whatever I wanted...usually a burger and fries followed by some ice cream. smile emoticon Once I lost the weight I got lazy about working out but continued following the 8 hour diet and was able to maintain. However, I recently noticed my weight creeping up so I'm exercising again to maintain....which is what I should have kept doing anyway for my health! Best of luck to you Daniel...I look forward to your updates. Here is a link to a story about the 8 hour diet in case you're interested in learning more about it: http://www.today.com/.../-hour-diet-watch-clock-lose-weight/ "

So yes -- one of the forms of intermittent fasting is book-ending the times in which you eat to only be during an 8 hour period. This creates an "8:16" fast -- daily you're getting at least 16 hours of fasting in.

Awesome to hear that this worked for you. Incredible, too, that it's not necessarily about calorie restriction (sometimes referred to as "CR") but about when you eat the calories. Just the timing makes a difference in a number of the studies I read up on.

Here's why I'm going for a more intense approach: I basically have a short-term and a long-term goal for fasting. The short-term goal is to get into better shape physically. But the long-term goal is to become healthier. The decision I made recently was to try not eating anything on my fast day (even though a 5:2 approach allows for ingesting 600 calories on a fast day while still maintaining the health benefits of fasting). I'm going to try this on my next fast day and see how I feel, because while I'm hungry on the afternoon of a fast day, by the evening I've lost those hunger pangs, and I really believe I can get through the whole day without eating without too much trouble.

Doing this will create a scenario where I'm doing a 36 hour fast 2x per week (basically if my fast day is on a Tuesday, that'll mean I eat dinner on Monday and then don't eat anything else until breakfast on Wednesday). But it doesn't feel like 36 hours because I'm spending at least 12 of those hours sleeping (i.e., on Monday night and Tuesday night). And ideally I'm spending more like 14-16 of those hours sleeping. So it feels like a really great "bang for my buck" approach to fasting. Two nights and one day of fasting. We'll see how it goes, and whether it's as doable as I'm hoping it will be.

This was what it was like to sit at lunch while my co-workers ate.

Here's an update after a long 10,000 meter workout, the morning after a fast day.

And here was a video from the night before -- a workout on the day of my fast