Fast way to better health
How would you like it if I told you there was a way to eat pretty much anything and everything you wanted to eat and still maintain your health? Or better yet, what if I told you that you could eat pretty much anything and everything you wanted and even improve your health? Would you be interested? I figured as much.
There is a way to reduce blood sugar, improve insulin sensitivity, reduce blood pressure, increase HDL levels, get rid of diabetes, live a lot longer, and still be able to lose a little weight. All without giving up the foods you love. And without having to eat those foods in tiny amounts. Sounds like a late-night infomercial gimmick, but it isn’t.
Before I get to the real nitty gritty of how such a thing can be done, let’s look at a method that has been proven in countless research institutions to bring about all the above-mentioned good things. It’s called caloric restriction.
When researchers restrict the caloric intake of a group of lab animals to about 30 to 40 percent of that of their ad libitum (all they want to eat) fed counterparts, they find that the calorically restricted animals live 30 percent or so longer, don’t develop cancers, diabetes, heart disease, or obesity. These calorically restricted (CR) animals have low blood sugar levels, low insulin levels, good insulin sensitivity, low blood pressure and are, in general, much healthier than the ad lib fed animals.
Most of the work in caloric restriction has been done on rodents, but there is a long term study on Rhesus monkeys (17 years at this point) that appears to confirm the rodent data on longevity and health with CR in primates. There are no human longevity studies, but there are a number of human studies on CR and health that show that human subjects under CR conditions reduce blood sugar, improve insulin sensitivity, reduce blood pressure, etc., so it stands to reason that if humans reduced their caloric intake by 30-40 percent for their entire lives, they would also live longer.
Caloric restriction is a terrific way to lose weight and get healthy; problem is, it’s not much fun. When rats live out their little ratty lives calorically restricted in their cages they seem to show signs of depression and irritability. Primates do for sure. If primates don’t get enough cholesterol, they can actually become violent. But, if you’re willing to put up with a little irritability, hostility and depression, it might be worth cutting your calories by 30 percent for the rest of your long, healthy miserable life.
Doesn’t sound so cheery? You’re not ready to sign up yet?
Well, there is a better way.
A number of different research teams have studied a method by which rodents can get all the health and longevity benefits of caloric restriction without calorically restricting. And the method has been studied in humans and seems to achieve the same health benefits and, if an old Spanish study can be believed, maybe even an increase in lifespan.
What is this magic method?
Intermittent fasting.
In regular fasting one goes entirely without food, which is caloric restriction carried to the extreme. Going entirely without food in the short term leads to improvement in health, but also leads to an extremely short life unless the fast is aborted.
Intermittent fasting (IF) is just as its name implies: a period of fasting alternated with a period of eating.
But isn’t that what we do anyway? We eat breakfast, then fast until lunch. Then, after lunch, we fast until supper. Then we fast all night. Uh, not exactly.
In research settings animals that are intermittently fasted are fed every other day, so they eat whatever they want for a day, then they are denied food for a day. Interestingly, on feeding days most of the animals eat a almost double the amount that their ad lib fed mates do. Thus the IF animals eat about the same number of calories overall that the ad lib fed animals eat, but, and this is a huge ‘but,’ the IF animals enjoy all the health advantages that the CR animals do, and, in fact, are even healthier than the CR animals.
Like caloric restriction, intermittent fasting reduces oxidative stress, makes the animals more resistant to acute stress in general, reduces blood pressure, reduces blood sugar, improves insulin sensitivity, reduces the incidence of cancer, diabetes, and heart disease, and improves cognitive ability. But IF does even more. Animals that are intermittently fasted greatly increase the amount of brain-derived neurotrophic factor (BDNF) relative to CR animals. CR animals don’t produce much more BDNF than do ad libitum fed animals.
What’s BDNF? (The Wikipedia definition is actually pretty good)
BDNF, as its name implies, is a substance that increases the growth of new nerve cells in the brain, but it does much more than that. BDNF is neuroprotective against stress and toxic insults to the brain and is somehow–no one yet knows how, exactly–involved in the insulin sensitivity/glucose regulating mechanism. Infusing BDNF into animals increases their insulin sensitivity and makes them lose weight. Humans with greater levels of BDNF have lower levels of depression. BDNF given to depressed humans reduces their depression. And Increased levels of BDNF improves cognitive ability. In short, you want as much BDNF as you can get., and with IF you can get a lot.
But, who wants to go all day every other day without food?
Well, you don’t have to. MD and I, using ourselves (selflessly, I might add) as subjects have worked it out.
Most rodents feed throughout the day and night, so restricting them for 24 hours does just that: it restricts them for 24 hours. In humans, however, the situation is different. We humans, for the most part, eat only during our waking hours. So if we fast for a day, we end up fasting for about 34 hours and eating for 14, which isn’t the same as 24 on, 24 off.
Let me show you what I mean.
Let’s say you pick a day to start. You eat all day, then go to bed, wake up in the morning and fast all day, then go to bed. You wake up the next morning and eat all day, then go to bed and start again. So, assuming you eat until 10 PM on your eat day, once you quit eating you don’t eat again until 8 AM 34 hours later. If you eat from 8 AM that day until 10 PM, you’ve eaten for 14 hours. so, you’re on (eating) for 14 hours and off (fasting) for 34. MD and I spent a couple of weeks doing it that way, and I’m here to tell you, it’s no fun. At least not on the fast days. The eating days were a different story; they were great, but we would spend the entire day dreading the fast day coming up.
We fooled around with a number of different eat-fast-eat regimens and came up with something that works pretty well. We set up our cutoff time as 6 PM. On the day we started, we ate until 6 PM, then fasted until 6 PM the next day. On the next day we ate supper right after 6 PM and ate breakfast and lunch (and a few snacks) the next day until 6 PM when we started fasting again.
The advantage of this regimen is that we were able to eat every day. One day we would get supper–the next day we would get breakfast and lunch. On no days would we go entirely without food. This schedule worked the best for us.
On the times during the day that we ate, we didn’t stick with our normal low-carb fare; we ate pretty much whatever we wanted, including a fare amount of higher carb stuff. We stuck with the regimen for a few weeks just to see if we could tolerated it, which we did just fine. We ultimately drifted back to our normal low-carb diet, however, just because it seemed to work better with our schedules. We could have been happy on the intermittent fasting regimen for the long term.
I would think that the optimal way to go would be to follow an intermittent fast using low-carb foods during the eating periods. One would get the best of all worlds healthwise this way.
Over the period that we followed the various IF regimens we lost a little weight because, unlike the rodents, we couldn’t eat twice as much during the eating days as we would have eaten were we not fasting. We didn’t check any lab work to see if any values had changed. We weren’t doing a hard core study; we were simply evaluating IF as a practical means for humans to use to improve their health.
In thinking about the process I came to the conclusion that IF was probably the way Paleolithic man ate. We modern humans have become acculturated to the three square meals per day regimen. Animals in the wild, particularly carnivorous animals, don’t eat thrice per day; they eat when they make a kill. I would imagine that Paleolithic man did the same. If I had to make an intelligent guess, I would say that Paleolithic man probably ate once per day or maybe even twice every three days. In data gathered from humans still living in non-Westernized cultures in the last century, it appears that they would gorge after a kill and sleep and lay around doing not much of anything for the next day or so. When these folks got hungry, they went out and hunted and started the cycle again.
If you buy into the idea that the Paleolithic diet is the optimal diet for us today because it is the diet we were molded by the forces of natural selection to perform best on, then you should probably also buy into the idea that a meal timing schedule more like that of Paleolithic mean would provide benefit as well.
One of the things MD and I took away from our IF experience is the idea that we don’t have to eat three meals per day. We now often skip lunch and don’t seem any the worse for it. Sometimes we get up and get going with all our projects and don’t eat breakfast. We try to skip a meal here and there because figure it’s probably good for us. When you get used to it, you don’t really even think about it. And it’s good for you. Don’t take my word for it–look at the medical literature.
There have been a few human studies on IF, and all have shown a marked improvement in virtually every parameter tested. None of the subjects in any of these studies has done the full 24 on-24 off that MD and I did. Most fasted until 5 or 6 PM on the fast days, then ate, then ate regularly on the eat days. Even with this wimpy IF schedule the subjects did better.
One of the recent papers published on the less rigid IF schedules caught my eye because one of the authors was Don Laub, who used to be the chairman of the plastic surgery department at Stanford. When I was in medical school I thought I wanted to be a plastic surgeon so I went to Stanford during a part of my senior year and worked with Dr. Laub as my mentor.
In this study, published in the journal Medical Hypothesis in March of this year, Dr. Laub along with two other physicians (neither of whom I know) underwent their version of and intermittent fast. The three of them have since May 2003 been on a version of the IF in which they consume about 20-50 percent of their estimated daily energy requirements on the fast day and eat whatever they want on the non-fast days.
Since starting their regimen they 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.
In their paper these researchers discuss a 1957 paper from the Spanish medical literature.
…the subjects were eating, on alternate days, either 900 calories or 2300 calories, averaging 1600, and that body weight was maintained. Thus they consumed either 56% or 144% of daily caloric requirement. The subjects were in a residence for old people, and all were in perfect health and over 65. Over three years, there were 6 deaths among 60 study subjects and 13 deaths among 60 ad lib-fed controls, non-significant difference. Study subjects were in hospital 123 days, controls 219, highly significant difference. We believe widespread use of this pattern of eating could impact influenza epidemics and other communicable diseases by improving resistance to infection. In addition to the health effects, this pattern of eating has proven to be a good method of weight control, and we are continuing to study the process in conjunction with the NIH.
There is much more to the IF story that I will continue in another post. I would do it in this one, but I (actually my web guy) upgraded my blogging software and somehow the little buttons that let me link to other sites are AWOL. I can’t italicize or set off quotes or do any of the things I normally do in the course of posting. I’m hoping that I will get this straightened out soon. When I do, I’ll go into the subject in a little more detail and show a chart that demonstrates the difference between CR and IF. (Note: the problem is solved; all links are working.)
In the meantime, if any of the readers of this blog would like to undertake an intermittent fast, I would love to hear the results of the experience. Please send a comment.
The sound of “eat pretty much anything and everything you wanted to eat and still maintain your health”, seems so unreal. Though it could happen to some individuals. I’d still believe in a balanced and moderated diet plan. Interesting post I have to say.
Hi folks – great post, great replies. I read them all, every last one, over the last week or so. Now I have a question about my weight loss during Intermittent Fasting (IF).
I’m a 51 year old male, 5’11”, and this year I used the low carb way of eating to drop from a BMI of 27.5 to 23 over the last several months. My goal is BMI 22, or 158 lbs – basically college weight.
I hit a plateau for several weeks & wasn’t dropping any more weight while continuing to eat induction levels of carbs, so I started IF just a couple of weeks ago. I do two 36-hour fasts (e.g. fast from Mon dinner to Wed breakfast) per week and I’ve completed four of these.
My fast is as honest a fast as I can make it – just coffee (no sugar or cream), iced tea, water, and chicken broth with a little extra pepper on fasting days. I drink a good amount of water (at least 3 liters) because I realize that caffeine is a diuretic.
My records show I’m losing about 2.5lbs during the fast and regaining 1.0 to 1.5lbs after each fast, so during each of these two weeks I’ve been fasting, I’ve lost a little over two pounds a week.
Now of course I don’t subscribe completely to the “3500 calories equals one pound” equation because I know the body plays games with the metabolism when given too many or too few calories. But what I wonder is this – if my typical diet is 2000 to 2500 calories and I’m only skipping one day of feeding, how am I averaging a full pound of real loss with each fast?
I love it but it seems impossible.
Wow, this is absolutely fascinating about BDNF.
This is of particular interest for me because I’m currently reading The Brain That Changes Itself (great book on neuroplasticity),and now this get me thinking that IF is like putting our brain’s on natural steroids. Awesome!!!
From personal experience, I’ve been doing daily 16 hours fasts for 10 days now, and my performance on Brain Training games at luminosity.com has risen significantly. I’ve also noticed that I feel sharp even on when I don’t sleep enough, which is totally new to me.
I started fasting to improve my physical performance in the upcoming Anaconda Race (world’s largest adventure race)- you can read the story at http://www.thefeelgoodlifestyle.com/fasting-for-fast-weight-loss-superior-fitness-and-better-health.html – but this BDNF idea just opens up a whole new world of possibilities.
Mind blowing stuff, literally.
Cheers from Australia!
Hi there. Nice writeup
I especially liked and thought about the part with allergies. I’m allergic myself (pollen, mainly), and during puberty I had enormous problems with it. Ofcourse, during puberty, a tall growing lad has to eat a huge amount of calories just to keep up with the basic metabolic rate, and eating that many calories requires either eating until you almost throw up or eating 5-8 times per day (which I did). I was told that “allergies are usually worst during puberty and sometimes even go away completely at the age of 18-20″. So far, this still seems to be the widely observed fact.
I still have some spurious problems with it, but mainly only around midsummer now (a very much observed holiday in sweden, with tons of food served many times per day). That’s quite interesting, since midsummer is usually a bit too early for fir and grass to be blooming fully where I live, but during the pollen peaks I generally have very little problems at all.
Do you think the less frequent eating patterns of adults compared to teenage guys could affect this? If so, just skipping food every other day, or even just skipping breakfast, might be a very good way of alleviating allergic problems. I’d be interested in your thoughts on the matter.
Thanks again for a good article.
I find it interesting that there are so many women reporting weight loss success with IF when on lots of the other threads there are so many women wondering why they can’t lose weight. I accidentally IFed last Wednesday, eating nothing after breakfast until breakfast on Thursday. I ate dinner on Thursday and then ate nothing except coffee with cream until dinner on Friday. I finally have seen some weight loss after 6 weeks of low carb and seeing nothing. I’m going to see if I can continue, at least every Wednesday since that is easiest for me, and hopefully a second day whenever possible.
I have been doing the daily fasts (i.e. eat between 4 pm and 8 pm every day). Sometimes i add low carb in and I tend to lose more weight but most of the time I still eat whatever i want.
With my last pregnancy I was gestational diabetic and my doctor told me that I would be for every pregnancy after that. It took be 2 years to conceive that pregnancy. After 6 months of IF I lost 37 pounds. I didn’t feel hungry during the day any more and my energy is increased.
We decided start trying to have another baby, expecting it to be a couple of years before I would get conceive. I got pregnant on the first try and I was NOT gestational diabetic with this baby. By the way, no, I did not IF while pregnant. I stopped when I found out but I was more intune with my hunger and I only ate when I hungry. I know that once I am done breast feeding and get back on IF, my baby weight will fly off of me. Not to mention that I only gained 20 pounds during the pregnancy because IF taught me how to eat!
I have been doing a form of this for about 8 months, and lately have been backsliding a little. I’m trying to get myself back on track.
My question is, if I slip a little and eat something, should I just bag it for the day, or do I still get some benefit if I stop it right there and continue to “fast.” (I’m using an eating window of 5 hours every evening).
Thanks for any advice!
The China Study is something to consider with this. I do IF as a practicality, but I’m also completely vegan. I have fluxuated from a vege to vegan diet the last few years. A couple years back I did the master cleanse, and followed up with disciplined eating schedules. My HGH went through the roof and I saw remarkable strength gains. I also became more tolerant to cold water and intense summer heat.
I really believe that finishing the evening meal while the sun is still bright is congruent with natural cycles. Ever tried lighting a fire in the dark?
You’ll feel fatigued at first if you’re used to high meat intake, switching to a plant based diet. Stick with it and you will add years to your life. Get plenty of saturated fat, coconut oil is great. If you have to have animal based fat, make sure it’s grass fed at least.
That´s an interesting alternative showing that what the body feels, such as stress, influences the body weight. Healthy food and mental psychologic health are linked.
I also could read that magnesium have various effects on our main organs and improve the mineral balance, helping the mood, sleep, appetite level… And a lots of people have deficiency of it!
is it ok to IF if you have adrenal fatigue? i’ve heard that you it’s important to eat 3 meals a day if you have adrenal fatigue?
I have no experience with anyone with adrenal fatigue (which is itself a questionable diagnosis) following an IF, so I can’t say from observation.
I have had adrenal fatigue.. it is much better now. I used to be so bad that I could hardly do much at all. Anyway, I don’t think IF is very good for when your adrenals are compromised. I found, doing IF, that at first I lost weight and felt really good, but after a while I stopped losing weight and started to get tired a lot again and having to take naps (it is almost involuntary, I HAVE to sleep, not normal tiredness) so I stopped doing it. Since then, I have done better eating low glycemic (got a blood sugar monitor and found I’m borderline diabetic- I didn’t think I could have real insulin problems because I work physically hard and ate decent but that’s apparently no guarantee!) and smaller meals more often. I don’t buy that idea of it keeping your metabolism up, but I think the reason it helps some lose weight is because they don’t ever spike their blood sugar. I think the reason I liked IF so much was because my body so craved having a high blood sugar that I only seemed to get from a large meal (I didn’t care for sweets a whole lot for the most part, not like you would think) so it was worth it not to eat in order to get to eat a real meal. I had a hard time feeling satisfied from food. Since going low glycemic (plenty of protein and fat, good fat that is), I have lost about 8 lbs. They have come off slow about a lb a week but all of it’s been from my belly. Also, my lower back pain is going away as have my stomach problems (the main thing is when I would run it would sometimes throw my stomach into unbearable cramps- I’ve had pancreatitis before and I’d say these are comparable, they’re that painful, also my stomach would overract to herbal laxatives). Now that I’ve done just low GI for a couple months, I think throwing a fast in here and there would be ok, but doing it too often was probably too hard on my adrenals much as I hate to admit it.
thanks ashley. that helps. dr. eades, IMO, adrenal fatigue is very real. a great book to read is “Adrenal Fatigue”, by dr. james wilson.
[ I left this reply on Oct 14 2011 but it never got added to the stream, so I'm trying again - ]
Hi folks – great post, great replies. I read them all, every last one, over the last week or so. Now I have a question about my weight loss during Intermittent Fasting (IF).
I’m a 51 year old male, 5’11”, and this year I used the low carb way of eating to drop from a BMI of 27.5 to 23 over the last several months. My goal is BMI 22, or 158 lbs – basically college weight.
I hit a plateau for several weeks & wasn’t dropping any more weight while continuing to eat induction levels of carbs, so I started IF just a couple of weeks ago. I do two 36-hour fasts (e.g. fast from Mon dinner to Wed breakfast) per week and I’ve completed four of these.
My fast is as honest a fast as I can make it – just coffee (no sugar or cream), iced tea, water, and chicken broth with a little extra pepper on fasting days. I drink a good amount of water (at least 3 liters) because I realize that caffeine is a diuretic.
My records show I’m losing about 2.5lbs during the fast and regaining 1.0 to 1.5lbs after each fast, so during each of these two weeks I’ve been fasting, I’ve lost a little over two pounds a week.
Now of course I don’t subscribe completely to the “3500 calories equals one pound” equation because I know the body plays games with the metabolism when given too many or too few calories. But what I wonder is this – if my typical diet is 2000 to 2500 calories and I’m only skipping one day of feeding, how am I averaging a full pound of real loss with each fast?
I love it but it seems impossible.
[ Update on Dec 29 2011 ]
I’ve completed 14 of these 36-hour fasts and also have been doing shorter fasts where I just skip breakfast and lunch. I’m just a pound or two away from my goal weight now – the fasting has helped me shed over 10 pounds since my plateau in October.
Overall I’m very happy with the results – I may not be losing a full pound from a single day of fasting, but I’m still finding intermittent fasting to be much easier to handle psychologically than trying to use portion control to reduce calorie intake. Although I haven’t really experienced a “euphoria” that some folks report while fasting, I do feel mentally sharper and I certainly get a euphoric kick out of the first meal I use to break my fast!
I’ll continue to use the 24-hour fast (skipping bkfst and lunch only) for maintenance in 2012. Happy New Year to everyone!
Geez Jim, I’ve pretty much do what you do, only 2- 36 hour fasts a week– been doing it for at least two years at that pace, I’m only about 10 pounds lighter than I was two years ago in the fall. I’m 57 5’4” about 190 lbs, I was about 200 back then. I’m a chubby little fella. There are so many postive testimonies here to the efficacy of IF, maybe it’s helpful to hear of someone that struggles in it? I don’t really struggle, cuz I like the way I feel doing it, and, I’d be 500 lbs if I didn’t. But it’s so odd that everyone looses significant wt. in such a short time and I’m still and chubbly little guy over two years of doing If?
Sounds interesting. I am 51 and 6 foot tall. I weighed 195 pounds 6 months ago and lost 25 pounds on caloric restriction. Now I weigh 170 pounds. Even though my weight is ideal for my height my wife says I look too skinny. Perhaps I can use intermittent fasting and get the benefits without losing further weight.
I think IF is the best way to go.
Hello Doc
I love this IF thing!
I just think maybe am not doing enough as I can’t stand coffee without cream and just having tea and water I get a little sick. I am VERY insulin resitant; I don’t know if I am hypoglycemic or that is what I am feeling. I do know if I eat breakfast skip lunch ugh really sick.
My question is am I am doing a little mostly harmless cheating (I do the fast every other day till 6PM thing three days a week) or am I ruining all my efforts? The most important thing is to have good blood sugar levels although I need to lose weight too. I do eat healthy, by preference. Thank you thank you!
@mory – you said ” it’s so odd that everyone looses [sic] significant wt.”. Dr. Eades doesn’t suggest significant weight loss is obtained with IF; you just get a number of health benefits from it. He mentioned losing “a little” weight because he & his wife “couldn’t eat twice as much during the eating days as we would have eaten were we not fasting”. At your BMI=33 (comfortably into the obese range) I’d wager you’d find the weight loss you’re looking for with a strict low carb approach. IF is an idea to consider when you’re at normal weight & considering ways to maintain that new weight.
@eran – Clearly 170lbs on a 6’0″ adult frame isn’t “too skinny” no matter what chart you might consult. At BMI=23 you’re in the middle of the normal range. Maybe you’re wife is just worried about the looks you’re getting from the other chicks
@Anne – If you’re saying that you’re “cheating” with a little cream in your coffee, it shouldn’t be too much of problem. I n a reply he made to a September 15, 2006 post by Esther Hoff (above), Dr. Mike said Dr. Mary does the same thing while IF’ing. I do kind of agree with him when he suggests folks should “buck up” and drink it black. Personally any food I label as something I can’t live without is one I should strongly consider living without – are you really a slave to a specific substance like *cream*? Oh wait, double standard, I can’t live without black coffee myself
I did want to add one more thing about IF to folks who aren’t already low-carbing it. Before I started low-carbing, I couldn’t imagine skipping a meal. If a meal was even an hour late, I always felt desperately hungry, fatigued, and very cranking. I’m pretty sure now that it was the blood sugar spikes & valleys caused by consuming carbs while being borderline insulin resistant – just like most Americans in middle age. So my strong suggestion for anyone overweight is to try a strict low-carb regimen first, and then consider IF only when you’ve reached normal weight. It’s the only way I could have done it.
Standard disclaimer: I’m not a physician and I’m only sharing personal experience.
Good luck everyone & keep this post alive!