My Half-Fast Diet

By Scott Charles Anderson

A little starvation can really do more for the average sick man than can the best medicines and the best doctors. — Mark Twain.

Lab rat

What do you mean, calorie restriction?

One of the most depressing studies in the already discouraging annals of diet research was conducted in the 1930s. That was when they found that lab rats could live longer if they just ate less. A lot less. A miserable amount less. You don’t have to follow this diet very long before the continuous, gnawing hunger makes you long for the sweet embrace of death. In the real, non-rat world, it might not actually extend your life, just your misery.

Caloric restriction requires obsessive dedication – not a good fit with my special forte of compulsive dissolution. But! Can we eat like a prince one day and atone on the next with a short fast? Oddly enough, that seems to work about as well as continuous caloric restriction. For rats, at least, intermittent fasting may even be better than constant privation.

So, how does the diet work?

For reasons that aren’t entirely clear (guts turn out to be complicated), occasional fasting has many long-lasting effects on your body. It lowers the sugar levels in your blood, (not all that mysterious with lowered food input) which dampens your insulin, which is good for your overall health. Type 2 diabetes starts with insulin resistance, which means your tissues don’t respond to blood sugars as well as they should. But your tissues become more sensitive to insulin after a fast, which is good news.

Fasting lowers your blood pressure, too. As an extra bonus, it seems to toughen up your neurons, helping them to better deal with injury and abuse. That brain-toughening act also seems to stave off Alzheimer’s. Well, at least the rat version of Alzheimer’s.

Interestingly, these effects are similar to what happens when you exercise. Which means you might be able to get some of the benefit of the exercise wheel just by backing away from the cheese wheel. My wife assures me, however, there is no way in hell that I am cutting back on my exercise. I had to marry a German.

Of course, those health improvements are nice, but the reason I bring up intermittent fasting in a Notch by Notch article is for a simple side effect: even though you can eat like a gourmand on your regular days, tossing in a fast every now and then helps you lose weight while making you healthier. Normally, you get energy directly from the food you eat, soon after you eat it. But if you don’t have any food in your intestines, you have to go after the fat you’ve been doggedly storing away over the years. Adios, adipose!

Alvise Cornaro

Alvise Cornaro preached moderation and sobriety. What a buzzkill.

 Although this diet is in the news lately, it really isn’t new. A fellow named Alvise Cornaro touted a diet like this back in the 1500s. However, he also touted sobriety, so a lot of people sought a second opinion. In no time at all, his theory was pretty much forgotten.

Hundreds of years earlier than Cornaro, several religions also instituted fasting regimens. Muslims around the world, for instance, start a month-long semi-fast called Ramadan in the summer. This is really a 12-hour fast, where no food is consumed from sun up to sun down. Unfortunately, you also give up water for Ramadan, which leads to a concentration of uric acid due to dehydration. In Islamic countries, that may have something to do with the higher rate of traffic accidents and sick days during Ramadan. The Koran notwithstanding, doctors tell you not to limit water when you fast, or any other time. If you thirst, then quench.

It’s not just Muslims who fast: Buddhists, Christians, Mormons, Hindus, Jews and Sikhs all have fasting built in to their religious observations. That’s a lot of history, demonstrating at least that millions of people can endure fasting. With such deep cultural roots and so many participants, intermittent fasting deserves some proper scientific scrutiny. Yet the first controlled studies weren’t done until the mid-1940s. They showed that mice on an intermittent fast lived at least 15% longer.

The average life expectancy today is around 80 years, so an extra 15% could take us to 92! And, if intermittent fasting can limit the depredations of diabetes and Alzheimer’s, they could be healthy years. We’re not rats, so our mileage may vary, but it’s an enticing scenario!

Once a week or once a year?

So what do they mean by intermittent? For rats, the researchers determined that the optimal timing is a complete fast one day out of three. But to make it easier on people who have to work for a living, at least one form of the diet involves eating for only 8 hours a day. That leaves 16 hours to whine. Fortunately, you can sleep though half of those hours. A tip: sleep in. This is the diet championed by David Zinczenko in his book titled The 8-Hour Diet. A version with different timing is presented by Kate Harrison in her 5-2 Diet Book. In this version you fast (well, you don’t exactly fast, but you only eat one quarter of the calories) for 2 days a week.

One nice thing about this diet is that I’ve unwittingly subscribed to it for years, based on my personal philosophy of moderation in all things, especially moderation. I followed a similar diet throughout my penurious college years, mostly due to a dubiously calculated decision to go with beer before bread. Turns out, you can skip several days of food if you have enough Budweiser. Okay, in reality, you need to limit calories or it’s not much of a fast, so you can’t drink college-portions of beer. Maybe one. Feh.

But now part-time fasting seems legit, even upscale. In a successful attempt to make my children groan, I call it my half-fast diet. Hmm, that joke sounds better than it reads. Anyway, intermittent fasting may be even better than caloric restriction at lowering glucose and insulin, making this a dynamite diet to inhibit or potentially reverse type 2 diabetes. I love any diet that can help stave off diabetes, which is not as much fun as people think it is.

However, if you already have diabetes or out-of-control blood sugars, this diet may not be for you. Fasting can cause your blood sugars to nosedive, potentially leaving you dizzy, moody and miserable. Check with your doctor before you attempt this diet.

I give it a shot

So on a fresh Monday, I decided to test it out. My plan was to fast for sixteen hours, from 10:00 at night to 2:00 the next afternoon. Giving up my night-time snacks was more painful than I anticipated, but I bravely soldiered through. The next morning, I was famished and had to stop myself twice from making breakfast on autopilot. But once I got to work, I basically coffeed my way through the day. Well at least until noon, when I started to vibrate and switched to water. It actually wasn’t too hard, although I whimpered a lot.

At lunch time, my co-workers left for lunch, and I stayed at my desk, forlorn in the quiet office. I soon broke the silence with an interesting side-effect of my half-fast diet: borborygmus. This is a wonderful word for stomach rumbling, the sound of gas gurgling through your intestinal plumbing. It was a loud and regular reminder that I hadn’t eaten yet.

Mouse cartoon

The next two hours dragged on forever. Why do they call it a fast when it goes soooo slow? Finally it was 2:00 and I snarfed down a spicy burrito for my late breakfast. Whew! I had made it through a whole half-fast cycle!

I’ve been on a semi-regular half-fast diet ever since. I still gurgle.

Can we wrap this up already?

According to its acolytes, the half-fast diet doesn’t require a 16-hour break every day. You can do it whenever you want, but — as with everything painful — it’s more effective the more often you do it. The best I can muster is once or twice a week. I will tell you this: I lose a couple of pounds every time I take the break. I typically gain a pound right back, but this means I can lose maybe a pound a whack. Not bad.

But not easy, either. I mean, planning-wise it’s pretty simple: no special foods (although actual healthy food might be advised) and no need for extra aerobics. (Hah! Extra aerobics! I made myself laugh.) But you still have to live with the rest of the world, and this diet puts you continuously out of sync.

Unless, like my wonderfully svelte wife Candyce, you work your ass off as a nurse. She regularly puts in 12-hour shifts without a legitimate meal break. She’s lucky if she can steal a sip of water between IV sticks and blood draws. In essence, she fasts every day, but in that hectic environment, she’s in sync with her fellow tortured nurses. By the way, this might be a digression, but we should give nurses a raise. You don’t even want to know what bugs have become resistant to drugs lately, and nurses are elbow-deep in them every day. Unlike say,science writers, they are real-life heroes.

I thought we were wrapping this up

For all of its little complications, the half-fast diet is a quick plan (it only seems slow) that you can implement whenever your clothes start shrinking. As another fat-busting weapon in the arsenal, along with lowered carbs and no sugar, it’s pretty reasonable — if you don’t count the borborygmus. But what’s a little gurgling between friends?

Be warned that some studies find no weight loss or even a weight gain in some people. The diet may lower your metabolism and, if you pig out on your days off, you can lose any benefit. If you gain weight on this diet, stop! Also, another study has found that fasting may lead to increased susceptibility to infection. However, this study was done on flies, didn’t actually use fasting but a treatment that mimics it — and the flies still lived longer.

Like all diets, you need to approach intermittent fasting with open eyes. If you give it a try, tell me what happens in the comments below!


Intermittent Fasting is an excellent site by Steve Mount that covers all the bases of intermittent fasting. Steve is a scientist, and looks at the research and data with a clear and unbiased eye. If you decide to try intermittent fasting, be sure to come back to this site for the latest studies.

Mark’s Daily Apple is the home of the Primal series of books (Primal Blueprint, Primal Cravings, Primal Connection) by Mark Sisson. He is a fine writer and goes into significant detail about intermittent fasting, like its effect on longevity, lipids, cancer, fitness and mental health. His verdict: “Fasting just seems right.” I agree.

James Clear is a weightlifter, photographer and writer who incorporates a LOT of intermittent fasting (350 out of 365 days a year!) into his schedule. He has a clear writing style and no axe to grind. He lays out the hows and whys with an appropriate amount of scepticism. His recommendation: try it and see if it works for you. Good advice!

Nerd Fitness is a terrific site run by Steve Kamb, a self-professed nerd. That is immediately attractive, since I’m nothing if not nerdy. He runs through the conflicting research, which is fun because so much of it is wrong. As a sceptical geek, he runs down the actual facts, upending reasonable theories that have no evidence to back them up. He concludes that intermittent fasting is a good idea because it’s simple and it works. Yep.

Mama’s Weeds is a fun, witty website devoted to getting healthy  and dropping a few pounds. Alison Spath is your guide, and she talks about several different ways to implement your intermittent fast. Like me, she finally settles on 8 hours of eating and 16 hours of fasting. Her favorite part of the diet is that she can eat all her happy foods like cream and dark chocolate. Yay!


Anson, R. Michael, Zhihong Guo, Rafael de Cabo, Titilola Iyun, Michelle Rios, Adrienne Hagepanos, Donald K. Ingram, Mark A. Lane, and Mark P. Mattson. “Intermittent Fasting Dissociates Beneficial Effects of Dietary Restriction on Glucose Metabolism and Neuronal Resistance to Injury from Calorie Intake.” Proceedings of the National Academy of Sciences 100, no. 10 (May 13, 2003): 6216–6220. doi:10.1073/pnas.1035720100.

Carlson, Anton, and Frederick Hoelzel. “Apparent Prolongation of the Life Span of Rats by Intermittent Fasting.” J. Nutr. 31, no. 3 (March 1, 1946): 363–375.

Halagappa, Veerendra Kumar Madala, Zhihong Guo, Michelle Pearson, Yasuji Matsuoka, Roy G. Cutler, Frank M. LaFerla, and Mark P. Mattson. “Intermittent Fasting and Caloric Restriction Ameliorate Age-related Behavioral Deficits in the Triple-transgenic Mouse Model of Alzheimer’s Disease.” Neurobiology of Disease 26, no. 1 (April 2007): 212–220. doi:10.1016/j.nbd.2006.12.019.

Mattson, Mark P., and Ruiqian Wan. “Beneficial Effects of Intermittent Fasting and Caloric Restriction on the Cardiovascular and Cerebrovascular Systems.” The Journal of Nutritional Biochemistry 16, no. 3 (March 2005): 129–137. doi:10.1016/j.jnutbio.2004.12.007.

McClure, Colin D., Weihao Zhong, Vicky L. Hunt, Fiona M. Chapman, Fiona V. Hill, and Nicholas K. Priest. “Hormesis Results in Trade-Offs with Immunity.” Evolution, June 1, 2014, n/a–n/a. doi:10.1111/evo.12453.

5 thoughts on “My Half-Fast Diet

  1. I have been eating just one meal a day for a few years now after listening to Dr. Dean Edell talk about it. Once I broke “habit” eating, I can pretty much eat whatever I want. I don’t know whether it will extend my life, but as a way of eating, it works for me.

  2. I love Dean Edell! He’s a long time intermittent faster, rarely eating more than 2 meals a day. I don’t know about life extension (although I’m still alive… does that count?), but like you, I like to take more control over things and break it up a bit. I always lose a little weight, but the best part is not having to cook or buy an extra meal.

  3. Great article!

    Intermittent fasting is indeed correlated with numerous health benefits and that’s just awesome. I mean, getting help with weight management is one thing, but health benefits too? Man, I was sold years ago and I’ve been practicing different forms of IF since.

    Here’s my thoughts on 36 hour fasts (likely to offer considerable health benefits if you can manage them)

    All-in-all, while special fasting days are quite clearly beneficial, they can be a struggle to adhere to. Our body likes to operate in a rhythm, so it can be difficult to break the feeding pattern. Because of that, many people feel better on a daily intermittent fasting system. Be it 16:8 or 20:4.

    I would especially recommend either the Leangains 16:8 diet or the Warrior diet which is basically eating 1x before bedtime. Both have tons of science to back them up, so google those.

    Keep writing these great articles!

  4. I find your writing extremely interesting. Can you believe I decided to fast today, about an hour before tripping across this article. What a coincidence. So now I’m armed with some great reasons to continue.
    I’ve found in the past if I skip the evening meal I feel much better the next day. How interesting is science and nutrition? Thanks and keep up the great work.

  5. Hi Scott, I have tried daily intermittent fasting for about a year now. I also did a couple of other things: Very little wheat and sugar, and also a boost of omega 3. So not that scientific…

    This is what happened:

    I lost some weight without trying. I was slightly overweight.

    My runny eyes and nose are normal again.

    The itchy red spots on my back are gone.

    I’m not bloated.

    My memory is better, I feel more positive.

    My hair is stronger, it looks thicker. And it grows longer.

    My eyes are better.

    My balance is better.

    And of course, you were waiting for it, my poops are adorably normal:-)

    No reason not to try this! People ask me if I’m hungry, and I am, but in a good way. I like that hunger, since I can eat a great meal every day. It’s good for the brain too go into hunting mode and look forward to a reward. It stimulates creativity.

    A hungry brain will get smarter in order to find food, that is just fact.

    Give it a try! So easy, so natural.

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