April 29, 2003
Alternating Days Of Feast And Famine Extend Life

Mice fed every other day had their rate of aging decreased in ways analogous to a calorie restriction diet.

Eating double portions one day and nothing the next delivers the same health benefits to mice as seen in animals whose lifespan has been extended by restricting their calorie intake.

Eat every other day and live longer. The rats fed every other day experienced lower blood glucose and blood insulin just as happens when on calorie restriction diets. But the rats fed every other day had normal body weight.

This might be doable with the development of an appetite suppression drug. One could take it before going to bed and then not eat the next day. Then wake up the following day and pig out.

Update: Mark Mattson, the NIH National Institute of Aging scientist who conducted the study, says skipping meals is probably beneficial.

Nevertheless, Mattson said, "I would be very confident in saying that healthy adults don't need three full meals a day and would be better off skipping one or two. When you go without food, there are benefits. Your cells become more efficient. I haven't eaten breakfast for 20 years."

Mattson said a study is being planned to test the effect of fasting on people. The plan is to compare the health of a group of people fed the normal three meals a day with a similar group, eating the same diet and amount of food, but consuming it within four hours and then fasting for 20 hours before eating again.

Here is the original press release from the NIH/National Institute On Aging on Meal Skipping Helps Rodents Resist Diabetes, Brain Damage.

A new mouse study suggests fasting every other day can help fend off diabetes and protect brain neurons as well as or better than either vigorous exercise or caloric restriction. The findings also suggest that reduced meal frequency can produce these beneficial effects even if the animals gorged when they did eat, according the investigators at the National Institute on Aging (NIA).

"The implication of the new findings on the beneficial effects of regular fasting in laboratory animals is that their health may actually improve if the frequency of their meals is reduced," says Mark Mattson, Ph.D., chief of the NIA's Laboratory of Neurosciences. "However, this finding, while intriguing, will need to be explored further. Clearly, more research is needed before we can determine the full impact that meal-skipping may have on health."

In the study*, published in the Proceedings of the National Academy of Sciences Online Early Edition the week of April 28, 2003, Dr. Mattson and his colleagues found mice that were fasted every other day but were allowed to eat unlimited amounts on intervening days had lower blood glucose and insulin levels than either a control group, which was allowed to feed freely, or a calorically restricted group, which was fed 30 percent fewer calories daily than the control group. Despite fasting, the meal-skipping mice tended to gorge when provided food so they did not eat fewer calories than the control group. This finding in mice suggests that meal-skipping improves glucose metabolism and may provide protection against diabetes, Dr. Mattson says.

In the same study, mice on these three diets were given a neurotoxin called kainate, which damages nerve cells in a brain region called the hippocampus that is critical for learning and memory. (In humans, nerve cells in the hippocampus are destroyed by Alzheimer's disease). Dr. Mattson's team found that nerve cells of the meal-skipping mice were more resistant to neurotoxin injury or death than nerve cells of the mice on either of the other diets.

Previous studies by Dr. Mattson and his colleagues suggested that nerve cells in the brains of rodents on a meal-skipping diet are more resistant to dysfunction and death in experimental models of stroke and other neurological disorders including Parkinson's, Alzheimer's and Huntington's diseases. Dr. Mattson also has found that meal-skipping diets can stimulate brain cells in mice to produce a protein called brain-derived neurotrophic factor (BDNF) that promotes the survival and growth of nerve cells.

Dr. Mattson and his colleagues are currently studying the effects of meal-skipping on the cardiovascular system in laboratory rats. The findings of this study, which compares the resting blood pressures and heart rates of rats that were fasted every other day for six months with rats allowed to eat unlimited amounts of food daily, should be available soon.


The NIA leads the Federal effort supporting and conducting biomedical, clinical, social, and behavioral research on aging. This effort includes research into the causes and treatment of Alzheimer's disease, Parkinson's disease, stroke and other neurodegenerative disorders associated with age. Press releases, fact sheets, and other materials about aging and aging research can be viewed at the NIA's general information Web site, www.nia.nih.gov.

*RM Anson, Z Guo, R de Cabo, T Iyun, M Rios, A Hagepanos, DK Ingram, MA Lane, MP Mattson, "Intermittent fasting dissociates beneficial effects of dietary restriction on glucose metabolism and neuronal resistance to injury from caloric intake," Proceedings of the National Academy of Sciences Online Early Edition the week of April 28, 2003 http://www.pnas.org/cgi/doi/10.1073/pnas.1035720100

It would be surprising to see pharmaceutical companies try to develop drugs that either stimulate the production of BDNF or that mimic the effects of BDNF.

Share |      Randall Parker, 2003 April 29 03:41 PM  Aging Reversal

Patrick said at April 29, 2003 7:23 PM:

Alternatively, just have a disorganised life. Worked for me when I was a uni student.

The next question is how often do you have to starve. One day in two works, what about 1 day in 3? 1 day a week?

Genevieve Marcus said at January 2, 2004 1:40 PM:

Other questions about fasting every other day: What, hypothetically, might be the effect on bone density? On cancer cells? On muscle tissue? On energy levels?

Randall Parker said at January 2, 2004 4:02 PM:

Bone density: I don't know. You might want to take calcium and vitamin D pills on the fasting days. Cancer: likely it would lower the risks of cancer. Muscle tissue: exercise could counteract any deleterious effect. B

Kelvin said at January 16, 2004 4:12 PM:

I have been fasting every other day for a short time and it seems to aid in weight loss. Is it true that my body will get used to this or does the eating of "normal meals" trick my body to thinking that there is no diet? I have heard both sides of this arguement and am wondering what your take is on it. Also, on fasting days, would a fruit or vegie help my motabolism?

Tim Campbell said at July 26, 2004 6:16 PM:

Would anyone have any comments regarding the transition to an "alternate day fast" lifestyle?

Bob said at August 16, 2004 6:52 PM:

I started fasting every other day in April 2003. At the beginning, I made an exception for the weekends but eventually I went to a strict every other day pattern and have been doing that for a year. I found that the biggest problem was what to do with the time that would have been spent on eating. I realized how much eating is an entertainment.

I have lost weight. I would say that it has not been that difficult to stick with the regimen.

Negatives include "stomach bad breath" on the fasting day. The only blood work I have done since starting this showed no change in total cholesterol but an increase in HDL and a decrease in LDL. But the triglycerides went up significantly as did fasting blood sugar. So I feel better but I'm not convinced it is entirely beneficial. I would like to enlist in a study where I could get more frequent blood work to see whether these numbers were a fluke.


Ralph said at December 10, 2004 9:17 AM:

Like Bob, I started fasting in (roughly) April 2003. I had good success at losing weight.

Blood pressure went from 160/120 to 120/75 without any medication. Wow.

Unfortunately, during the 2003 holiday season I stopped the diet and gained a lot of that weight back. Iíve been too scared to look at my blood pressure.

I returned to that diet about three months ago. The weight is coming off again. Iím beginning to feel good again.

This diet is most effective (for me) when combined with at least 20 minutes/day of cardio exercise. To say I hate exercise is total understatement. I have never experienced the runnerís high. The exercise does not get easier although my stamina seems to improve.

My treadmill tells me that I burn about 200 calories for that 20 minutes. Thatís about two handfuls of candy. I eat lots of candy on my eating days. In other words, the calorie consumption generated by the exercise has nothing to do with weight control. What I do find, though, is that exercise does a good job of killing appetite.

On my ďeating daysĒ I simply ignore any calorie restrictions. I try to exercise before I eat. I have soul-satisfying meals. I do not feel deprived.

On my ďnon-eatingĒ days I restrict intake to a single apple, an 80 mg aspirin, a multi-vitamin, and a garlic pill.

Somewhere around 5 pm on my non-eating days I start getting hungry. For about two hours the desire to eat is a bit annoying. The feeling passes. Remarkably, when I wake on my ďeating daysĒ I have absolutely no appetite. Itís, ďI know I can eat so there isnít an urgency to eat.Ē

OK, let me be a little gross. I have Irritable Bowel Syndrome (IBS, colitis) since I was a young boy. A colitis attack is awful. Terribly painful. Fortunately, it is over fairly quickly. Itíd rather have that than a migraine (which Iíve only had twice in my life). The apple-a-day regimen completely eliminates the IBS for me. For me it is truly ďAn apple a day ÖĒ

Eating small meals is just too damn difficult for me. Worse, it makes me feel constipated far too often. A really big meal - and the apples - generates a very satisfying bowel movement. Doing exercise also helps with the satisfying bowel movements. Sorry for being gross.

The apple-a-day regimen has reduced my colitis attacks from one a week to once a year. The diet and exercise seems to have improved intestinal motility.

Like Dr. Mattson, I havenít had (regular) breakfast since birth. Like my mother, if I eat breakfast I feel really crumby the rest of the day. I eat breakfast on rare occasions and when I do I rest for the remainder of the day. I usually eat a big dinner. This regular large-dinner cycle caused me to gain a lot of weight. 5í8Ē @ 230 pounds. Iím still way overweight (200 pounds). At my lowest, I was 175 pounds. Overweight by the charts but I looked pretty good.

I feel really terrific. Iím 54 and have no aches or pains. I feel very young. My brain is sharp and, I hope, getting sharper.

I, too, would love to join any controlled experiment. I, obviously, think that Mattson is on to something.

One last question: My wife complains of my bad breath. I think it is "stomach bad breath" that Bob, above, said he gets. Does anyone know how to combat this (other than to eat)?

Snez said at December 29, 2004 7:13 PM:

Does anybody know if any extra research has been done? If so, how do l find it?

I also have a few questions about caloric restriction and l can't seem to find someone who can answer them.

If anybody could help. thanks.


Gary said at April 7, 2005 8:38 AM:

>>I think it is "stomach bad breath" that Bob, above, said he gets. Does anyone know how to combat this (other than to eat)?

Chewing gum. I try to have it handy whenever I'm going to be talking. But chewing all the time makes my jaw sore, and sometimes people are more annoyed by the chewing than the breath.

Cathina said at May 18, 2005 7:45 AM:

I'm thinking of trying to fast every other day ... this is my second non-eating day (5/18) and it doesn't seem too bad (I have done a 2 week fast once in the past).

Where can I get more details on people who have tried this? I eat about 1700-1800 calories on my eating days and I am 5'3"/140 pounds. I want to know if my body is going to get messed up and if I'll gain weight like craxy if I stop doing this ...

If you know where there is more factual information on this method, please email me at cathina@twobigfish.com.


Eric said at May 26, 2005 9:08 PM:

To me eating every other day fits my personality.
I eat on odd days. 1st, 3rd, 5th, etcetera.
Double the calories for a 23 to 24 Body Mass Index (BMI)
Me 6 ft eat 4000 Kcal on eat days.
Less than 200 on fast days. Drink coffee, water, Fizzy water, Fat Free chicken broth and diet jello on 'fast' day
Like others report I generally do not get hungry till the afternoon of fasting day.
I like the odd day eating. on months with 31st I eat on both the 31stModerate 2100 Kcal and 1st 4000 Kcal.
There have been some human studies. I think the grumpy irratation on fast day can be overcome with diet jello, Fizzy water ( I like Pelligrino as I lived in Livorno Italy) $12 a case at Sam's $14 at Trader Joe's.
I will be interested to see the long term benifits of intermittent fasting that results in 'normal' body weight versus the 33% calorin restiction that results in skinny body type.

kinx said at June 5, 2005 9:43 PM:

i really need to lose weight, im not overly big, but i have alot of peer pressure from friends to lool "good". would fasting everyother day be ideal for me to lose some weight, but still be healthy?

sr said at July 3, 2005 4:12 PM:

I have maintained an intermittent fasting pattern for two years. Every other day -- ideally, 12 hours out of the 48 for eating, 8 am - 8 pm EOD. I have not lost weight, but am leaner with more muscle. Last year I put a pullup bar between two lintels in our apartment. Pullups are intense. Those, pushups and walks -- I used to run some. Recently I added a tablespoon of turmeric and a little cinnamon each day, fasting or not. The psychological effects are perhaps even more interesting than the physical.

terrance jolley said at November 23, 2005 11:14 AM:

The Most Honorable Elijah Muhammad taught us that eating one good meal a day between 4-6 p.m. would extend our life. He said one meal every two or three days would extend our life even further. He taught us to leave meat alone if possible and leave certain vegetables alone because of their reaction in the stomach field peas certain beans etc. regardless of their nutritional value. He said that eating one meal every three days could extend some of our lives to a thousand years, this is the way some of the old partiochs in the bible ate that allowed them to live so long. but the most important thing is to have positive thaughts because the brain effects the digestive system.

p.s. no smoking or drinking and absolutely no pork.

John Daugirdas said at January 23, 2006 10:41 PM:

Very interesting. I use a similar diet (described at eatqod.com and in a recently published book) but take in some minerals, some carbs, and some high biologic value protein during the OFF (fasting) days, for a total of about 400 calories. I think you absolutely HAVE to take in calcium, probably at least 800 mg/day, and vitamin D to prevent negative calcium balance. Also fiber and water intake are needed to prevent constipation. Some high-biologic-value protein (20-30g/day) controls hunger and maintains muscle mass, plus the main thing is, you need to take in some sodium and potassium/magnesium to maintain your mineral intake. I take in 2 g of each (sodium and potassium) - mostly as tomato-vegetable juice or as vegetable (squash, spinach) soups or just steamed vegetables with some dressing based on drinkable yogurt (Kefir).

For the OFF days, I've started to take in protein as protein powder (egg, whey, or soy, sort of in alternating fashion) - and I also take some of this if I don't have access to good sources of protein during my ON days.

With regard to "stomach" breath - probably ketosis. I don't think ketosis is necessary. That's why I never liked Atkins, although controlling carb intake is important. Take in some orange juice - or keep a tangerine on the countertop and eat a few slices if you feel the need for carbs. Nice thing is you break the cycle of mindless eating and develop the ability to identify specific hungers for specific types of food.

John Daugirdas

Rebecca said at March 25, 2006 10:55 PM:

I am a "bulk" eater...always have been. I always been interested in food, interesting and exotic food. I have never been famous for denying myself much. These three things have, as one would naturally imagine, contributed to significant weigh gain with age.

So this alternate-day diet works for me. I typically gain/lose 4 pounds a day on the alternate day eating program. On one day, I definitely enjoy having no diet restrictions of any type. I allows for me to experiment with many foods and recipes.

Alternatively, on the fasting day, I experience what I have read from research, that the hunger does not go away on that second day. But this has improved my overall ability to exercise discipline, in a good way.

I had lost a great deal of weight via calorie restriction and exercise during the year preceding this alternate day fasting. Alternate day fasting works for me, because it does allow me to eat what I want on the "food" day. Calorie restriction never permits me to "let up" and eat some fun foods. Alternate day fasting permits this, and that is a genuine treat.

I have not lost much weight on the alternate day fasting regime. However, I haven't been at it that long. It has, however, kept me from regaining the 156 pounds I lost.

I am borderline diabetic. The alternate day fasting seems to be keeping this in check nicely, although I do occasionally experience a few high blood sugar symptoms after a big eating spree in the evening of the "eating" day. I find it is better to "graze" on the eating day rather than having large throw-down meals or lots of sugar.

Another benefit of alternate day fasting for me is that there is ALWAYS plenty of energy for exercise, even on the "off" days....whereas a long term calorie restricted died often left me too weak to really enjoy getting out on long distance walks and other active exercise.

I plan to stick to this program a while, as I am a cancer survivor. I believe there are benefits for cancer patients in this program.

Rebecca Kimber
Age 56

Robbie said at December 20, 2006 8:08 AM:


Eric said at January 28, 2007 7:08 AM:

Inspired by a book called "How to Eat to Live," I have experimented with restricting meals with tremendous success.

I have been eating one meal a day for almost 8 years. Before that, I cut down from three+ meals to two meals a day in 1992-1998. I've been vegetarian since 1992, not touching animal flesh (sometimes eating things with dairy or eggs). It totally rehabilitated my immune system. Catching colds, flu, etc. became a thing of the past. If I eat more than once a day, I really feel sluggish and I tend to catch some kind of cold. However, in the past three years, I started catching nasty colds and feeling like I really needed to do some real fasting 48-72 hours. I knew I had to move to one meal every other day. My body was right. Now--along with eating one meal a day--I fast on Mondays (last meal Sunday and first meal Tuesday). It has really helped. I've been doing this for the past few months. Now, I feel my body telling me that I need to move into one meal every other day (especially after reading your testimonials).

I take a vegetarian multi-supplement before my fasting day. On the fasting day, I drink a little water, a homemade smoothie made with banana, raspberry and enriched vanilla rice milk and sometimes apple juice. The apple juice suppresses my hunger. I haven't had bad breath problems. But when I do, I put a clove or peppermint leaf in my mouth. The fasting days are always great times to focus on big projects for work. However, the hunger pangs can get really bad (slightly nauseating). Again, that may be because I'm fasting on Mondays and more days are in order.

Historically, I've never been overweight nor have I had blood pressure problems.

Good luck and take your time. Everyone's body works differently.

William said at June 3, 2007 9:26 AM:

The concept of fasting every other day produces tremendous benefits if followed correctly.

Some points I would like to make:

1. Many posts on this thread refers to adopting a diet of fasting every other day or eating once per day.....yet each one states how a little bit of this, some of that, some fruit, milk, juice, some pills, spices etc. are consumed on fasting days. That is not fasting.......and it will defeat many of the benefits to be gained. The purpose is to allow the digestive system a 'complete restí thereby allowing optimal regeneration and rejuvenation.

2. Couple this concept with optimal nutrition and you will increase the benefits tremendously. Optimal nutrition, that is to say:

Superfoods: bee pollen, raw honey, various sea salts (himalayan, etc.) seaweeds (dulse, kelp, etc.) raw cacao, nutritional yeast, raw maca root powder, certain berries, and others...

Probiotics: traditional sauerkraut, kimchi, beet kvass, and other fermented veggies. add also some raw fermented dairy such as goat yogurt/kefir and buttermilk.

Protein: raw dairy, very lightly cooked organic grass-fed organ meats, raw fish, and raw eggs or just yolks (other options are available)

Fats: raw butter and raw animal fats as well as cold-pressed oils such as hemp oil, olive oil, primrose etc. and possible inclusion of cottage cheese/flaxseed oil blend (based on Johanna Budwig's discovery...look her up)

Complex Carbohydrates: some grain may produce high benefit depending on the individual such as, buckwheat, quinoa, oats, wild rice (all soaked and cooked long enough)

Oraganic Vegetables: sulfurous choices such as garlic, onions and scallions. dark green veggies such as dandelion greens, parsley, cilantro (recommended is blending these in with something such as budwig/flax mix, as opposed to juicing). carrots, radishes, occasional potato, tomatoes.......and other veggies based on individual preference and toleration.

Organic Fruits: berries, apples, kiwis, pineapples, papaya etc. (best may be local in-season)

Spices: cayenne, turmeric, cinnamon, cloves, etc.

Anyone could tweak the above to their own standards as they are just options and opinions. Predominance of the diet should possibly be raw. Certain individuals may benefit more from a higher amount of cooked depending on genetic predisposition and ancestry. I would highly advise not creating a diet "too varied". Keep it simple, choose some of each that agree and rotate others in occasionally. Too much worry over obtaining nutrients from a wide array of substances can be unhealthy...I know from experience. Keep it simple. Remember, sometimes it is of higher benefit to eat with the season and what is produced locally.

3. Spiritual intent was mentioned and is very important. Our thoughts should remain healthy and whole. Some form of disciplined contemplation, or meditation could contribute massively to the above regimen. Living to serve others is of highest benefit to the greater self. The freed up energy not spent digesting could be implemented towards the bettering of others on the whole!

4. Just upon the simple contemplation of fasting every other day or allowing the body 24 hours between meals, one can clearly recognize the overwhelming benefits. We have simply bought into a dogma of eating so often based on the society of commerce in which we live. A system and group of individuals, that profit highly from informing us to do so. One can reason that it does not appear natural for a human being to be eating constantly. It took sometime to realize this on my own. I am quite joyful that Iím not too far along into life to not be able to benefit from such a concept. Teach others this information with compassion and a true intent of bettering their lives. Teaching by example and not preaching is still an attractive way to go. Best wishes and highest happiness to you all upon this journey!

Long Life and Best Intentions,

Adam said at August 8, 2007 10:20 PM:

I would never contemplate drinking anything during fasting, drinking fosters hunger, when you fast properly (neither drinking or eating anything) you are never hungry nor thirsty, I've gone two weeks without eating a thing and barely drinking anything and not on purpose I simply wasn't at all hungry nor thirsty and at the conclusion ate simply because I could not remember the last time I had anything to eat and felt guilty about it (when I checked my notes it was two full weeks since I ate). I do however take daily vitamins and herb capsules, perhaps that is considered cheating, don't know, don't care, its nutritious and healthy and I'm not trying to compete or be in competition with anyone. When you cut down your fluid intake your hunger goes away entirely. People on here say they feel hungry after one or two days of not eating anything, try not drinking anything and you wont have that problem (I brush my teeth daily and wash out the taste with water, but rarely ever swallow when fasting). Normally though I try to fast with a good three to four days between periods, that way my metabolism is kept at its highest and I always retain strength. The first day I fast I drop a good three to three and a half pounds, if I were to fast a second day in a row I might drop a half pound more but would be just as likely to not drop a thing at all so it just isn't worth a decrease in my metabolism to do it (a third day of fasting is also a wash but makes me a bit constipated). Weight wise I'm somewhere in the under one percentile range for my height, age, weight, which is rather ironic since I have excellent muscle tone (out of 100 people my height, gender, and age 99 of them are expected to weigh more than I do).

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