Modified Fasting: a good weight control strategy?
People fast for many reasons: as a religious observance or spiritual ritual, as a political protest, in preparation for medical procedures, or as an occasional health practice. And studies have confirmed that short-term fasting can have a number of health benefits.
Yet fasting for the purposes of losing weight is not generally seen as a good idea.
One argument is that you need to learn healthy eating habits in order to achieve long-term weight control. Fasting is by necessity a short-term strategy. Sooner or later, you have to begin eating again. And skills such as exercising portion control, choosing more nutritious foods and fewer empty calories, eating more vegetables and whole grains are not developed by fasting.
And we've all heard the argument that people who skip meals (whether one or a whole day's worth) tend to eat more calories later to compensate. (More on that in a moment)
But a series of new studies, summarized in the U.S. News and World Report, suggest that there may be a legitimate role for modified fasting as a weight loss tool.
A group of researchers in Louisiana conducted a small study in which overweight subjects ate just 20% of their normal caloric intake every other day. On the days in between, they ate as much as they wanted. On average, they lost about 8% of their body weight over the next two months.
Inspired by these results, Kenneth Webb decided to try his own version of the program. Webb calculated his daily calorie requirements (you can calculate yours with our Daily Needs Calculator) and ate just 30% that many calories every other day. On the alternate days, he ate 130%. Over the course of about seven months, he lost 30 pounds. Not surprising, because he reduced his overall calorie intake by about 20%. But Webb says his one-day-on, one-day-off routine has a psychological advantage: He claims that it's easy to be disciplined for a single day, knowing that the next day he'll be eating as much as he wants--with no guilt.
There appear to be health benefits to fasting as well. Short-term fasting has been shown to reduce the risk of heart disease, improve insulin sensitivity, and slow the cellular aging process. In a previous post, which generated an enormous amount of discussion, I discussed calorie restriction (CR) as a life-extension strategy. Some research suggests that fasting every other day may be almost as effective (and far less difficult) than the practice of caloric restriction.
Still, fasting isn't for everyone. For some, going an entire day on just a few hundred calories is simply too uncomfortable. For others--especially anyone who has struggled with eating disorders--the alternating sequence of fasting and feasting may lead to out-of-control binging. You'll have to be the judge of whether this strategy is a good fit for your lifestyle, disposition, and relationship to food.
And if you do decide to try it, remember that when calories are limited, the quality of them matters even more. On your fasting days, be sure to concentrate on nutritious foods like fruits, vegetables, and lean protein.
A final thought: We've all been led to believe that skipping meals is an ineffective way to lose weight. But research from Cornell University suggests that restricting calories for one meal per day may be an effective weight loss strategy.
In a small, 2-week study, one group was given a 200 calorie (kcal) lunch (such as a cup of yogurt or bowl of soup) and another was given a 600 calorie (kcal) buffet lunch. Both groups were allowed to eat as much as they wanted the rest of the day. Suprisingly, those who ate only 200 calories for lunch didn't seem to compensate by eating more the rest of the day. In fact, their daily calorie intake was, on average, precisely 400 calories less than those who ate the larger lunch, leading to weight loss.
Time for you to weigh in (so to speak!) on this interesting topic:
Have you ever tried modified fasting as a weight control strategy? How did it work for you?
Do you think every other day fasting would be a workable lifestyle? Easier than dieting every day? Or do you think its just a gimmick?
Would the possible health benefits of fasting, aside from weight control, motivate you to try this approach?
I look foward to your comments and discussion!
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Posted by: Sheridan Jackson | Mar 18, 2009 5:32:24 PM
I used Dr Airola's broth fasting method with great success. It involves eating nothing from Sunday evening to Tuesday morning but a broth made from onion, celery, carrot, parsley and pure water. I went down to 155 lb from 170, felt great, had lots of energy.
Posted by: Pat | Mar 11, 2009 7:48:09 AM
Interesting tibit...my 2 boys, who are 13 and 11 have been eating like this their whole lives. We laugh and say it must be an eating day today. The next day they barely eat, and they are both very healthy. They eat when they are hungry and that's it...
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Posted by: T-Loag | Aug 4, 2008 1:38:23 AM
I read about this on the Runnersworld website and I just had to try it. Not because I needed it either(im 16, 5'8 and 135). I wanted to see how it worked out. Well, I lost 2 lbs the week I did it. It worked for me anyway.
Posted by: Sabrina | Jul 17, 2008 4:24:57 PM
I was wondering if you might email me back (I dont really get online much except to check email)....
I have heard fasting one day a week is good for you. However, I am starting a diet regime and trying to lose weight. Is fasting with water one day a week counterproductive or...will it help/enhance/whatever weight loss. If it is going to hinder I would rather start fasting one day a week when I am at my goal weight-Ive just heard it is good for other things as well.....I'm not sure whether to start or wait, can you help me with this ? I can't seem to find someone to ask this who does fasting........thank you :) your post was uplifting!
Posted by: Monica Reinagel | Mar 3, 2008 8:13:32 AM
Bobbie,
a strict fast would involve drinking only water (for Ramadan fasts, Muslims actually have neither food nor water until after sundown each day). But we're talking about a modified fast in which you might eat 500 to 1000 calories. Some people have only vegetable and fruit juices, some have steamed vegetables, eggs, dairy or other protein. I guess you'd have to figure out what felt right to you.
Posted by: Michelle | Feb 29, 2008 8:00:04 AM
thank you Jill and runtolive, I too, eat this way basically, filling up (indulging) on the weekend when out with friends and then restrict through the week. When I eat a large amount 1 day , I am not hungry the next 1 or 2 so I eat very little. I am running 25 miles/week and that is fine. My family do not understand this and think I have an eating disorder (when they eat alot one day they are starving the next day - not me!) I am 5'2'' and 95 lbs which my doctor says is fine for my small frame. Thanks for making me feel 'normal'.
Posted by: bobbie | Feb 28, 2008 11:16:28 AM
Ok this is interesting, and a stupid question here, but when you say fasting, what are you actually allowed to drink, veg juice and non sugary drinks? Or just water? I would like to try this myself, but I think I would need something to carry me through the day. What about coffee and caffine in general?
Posted by: Tracey | Feb 28, 2008 10:37:05 AM
This sounds like a healthier, or at least more controlled, version of a "trick" I discovered in the last couple of years. When I hit a plateau in my weight loss, I indulge in a high-calorie day (usually a guilt-free trip to the buffet), then spend the rest of the week consuming a slightly-lower-than-normal amount of calories (maybe 10-15% less each day?). And I always lose weight. I had seen something like this called "re-feeding". I feel like giving my body all those extra calories and then cutting back sort of "resets" the mechanism.
Posted by: Karla | Feb 28, 2008 9:28:33 AM
Fasting has always been an interesting topic for me. I've not tried it (other than acidentally), so I can't be one to judge. I have heard from plenty of sources that fasting really does make your body feel better and, in some cases, look better. If people are having a hard time sticking to another diet or weight loss program, they should give fasting a try because it seems to me that people have got some impressive results.
I would like to try fasting at some point in my life, but I don't think I'm quite ready yet. I'm training for a marathon and I find myself hungry all of the time! This is fairly normal since I'm logging about 35 miles per week right now. Once the marathon training is finished, though, I'd like to give fasting a chance.
On another note...
We all know there are thousands of weight loss products and programs that are just full of crap. I agree with JB, a balanced diet and exercise WILL get results. People often will tell me that they wish they could have a lean body like I have, that they wish they could have genes like mine. This body has nothing to do with my genes!!! I make good choices when I eat, don't drink alcohol, get plenty of sleep, and get some sort of exercise everyday. I wasn't always like this and it was a long and rough transition from eating Taco Hell almost daily to watching everything I put in my mouth. It's a sacrifice, and, like most sacrifices, it's well worth it. I feel like a brand new person :)
Posted by: JB | Feb 27, 2008 6:52:40 PM
This, like every other "miracle diet", has got to have long-term metabolic effects. There is no great mystery to losing weight. This society is so focused on the "quick fix" that we have entirely lost sight of reality. Not only that, we are entirely too focused on the number that pops up on the scale. If you eat a balanced diet of a resonable amount of calories EVERY DAY, AND do a reasonable amount of strenuous exercise (this does NOT include gabbing on the cell phone while "running" on the treadmill or a leisurely stroll on the eliptical while catching up on the latest gossip) you WILL lose weight. Get help from a REAL nutritionist to put numbers on your BMR and activity level that is needed to lose the weight. It works!!! It really does!!
Posted by: marcus | Feb 26, 2008 2:43:06 PM
not eating gives your digestive system a break, reduces oxidative stress from the metabolism of food, promotes discipline, cleans you out, and actually feels good both physically and mentally .. nothing to freak out or worry about if you fast once a week, or a few times a week, provided you know how to eat right when you are eating. i'm a vegetarian, going vegan, so i already feel good (=. fasting is just another insight on how to be super healthy, if done right. ^_^
Posted by: Sasquatch | Feb 26, 2008 1:02:38 PM
I've been doing a weekly 24-hour fast for several months. It's not for weight loss, just general health. I like it. It seems to improve insulin sensitivity dramatically and put the body in fat-burning mode.
I don't regard it as dangerous at all, in fact I think it's very natural for our species to go without food for short periods of time. I think what's unnatural is having a caloric surplus all the time. Just to be clear, my total caloric intake is high; all I'm doing is shifting the calories from the fast day to the others. It's hard the first time but it becomes easy over time.
And as for the long-term effects, if the mouse studies are any indication, they're along the lines of increased lifespan, decreased risk of chronic disease.
Posted by: jill | Feb 25, 2008 8:02:31 PM
Like runtolive this is basically my diet. Not for nothing, I am hungry the next day if I miss a couple of meals but if I "overeat" one day, it kind of fills me up for the next day so I eat less. I am 5"4 and weigh 110lb with a weight gain since I hit 45. I have no problem with my working out 5 days a week (weights and/or running-I run about 25 miles per week).I think most people eat because they think they should be eating-not because they are hungry. FYI to Julia: once your body gets used to it the headaches will go away. It is like cutting back on coffee.
Posted by: julia | Feb 25, 2008 7:24:38 PM
I would love to do this but if I go hours without eating i get a terrible headache. What does the headache means and how best to avoid it using this method? This headache is one that can not be ignored, then I turn cranky until I get something to eat.
Posted by: runtolive | Feb 25, 2008 7:02:52 PM
Interesting, I think that this is basically how I naturally eat. When I've eaten like this in the past, I've never had problems keeping the weight off. Recently I've been trying hard to maintain a certain amount of calories a day and eating 3 meals and 2 snacks a day when I'm not even hungry because that's what most people recommend for weight loss. Recently I've been putting on unnecessary weight. I'm going to forget trying to think about it so much and go back to my natural way of eating. Think I tend to alternate days of eating a lot one day and then barely any the next. Probably keeps your body guesssing and your metabolism revved up even when you're eating smaller amounts on the low days. Thanks for the article. Forget my 5 meals of a regular amount of calories a day. I'm going back to my old ways!
Posted by: Justin Scott | Feb 25, 2008 6:35:19 PM
My first fast occured a few years ago when I tried to shed the last remaining pounds to reach my 100 lb. weight loss goal. It helped and I made my goal, but fasting was just a small part of my overall weight loss plan. I continue fast, usally 1x per week on Mondays because I allow myself a slight indulgence on the weekends (you gotta live, right?) and fasting helps me to get back on track with a healthy state of mind at the top of the week. I fast consuming nothing more than water, maybe some juice. Fasting helps me to remember that I have complete control over food, and it will never control me. I see it as a body cleansing of toxins and fasting actually helps me to be more health conscious for foods I'll eat throughout the week. It also helps me to focus on portion control other days- I figure if I can make it through Monday then portion control the rest of the week is no problem. I don't eat more the next day because then the fasting would be all for nothing. I'm still active while fasting, although I keep it at simple activities, like walking. I've noticed that while I fast I am highly mentally alert and actually have a burst of energy in the morning. I've also noticed that fasting has helped to train my body with smaller food portions- the less I eat, the less I want, and need. I keep my food intake around 2,000 calories per day and I'm active 5 or more days a week with running, biking, soccer, walking. For the past few years this has seemed to work well for me and has helped me to keep the weight off.
Posted by: Candy | Feb 25, 2008 3:39:43 PM
Since early June, 2007, I have been maintaining a Daily Caloric deficit of 1000 Calories by dieting and exercise.
I went from 210lbs to 160lbs by the end of Nov.
However, my weight loss slowed down at about the same time that I was becoming bored with my diet, and I went back up to 170lbs during the month of Dec.
At that same time I read about the "Johnson Up Day Down Day Diet" which was designed to keep the body from going into starvation mode and conserving fat Calories.
I decided to go one better and just eat to Maintenance level on every other day and not eat at all on the alternating day.
In order to not be fasting on any Sunday and to be able to count on some days as always being fast days and others as always being eating days, I started fasting on Mon, Wed, Fri, and alternating Sat.
My weight loss kicked right back in again, and I've been quite content with this method.
I continue to exercise on my fast days just as I do on my eating days, and I haven't seen any diminution of energy.
Posted by: Steve | Feb 25, 2008 2:16:06 PM
This idea of intermittent fasting is interesting. I've never thought to put a label on it, but I've been doing this for 3 years as a marathoner.
As a distance runner, I've always kept a decent weight (5' 10', 155) but I know my "ideal" racing weight is about 142lbs. I like to eat junk food, which prevents me from achieving my potential. So, I started eating only about 200cal for breakfast and 200-300cal for lunch and then I eat what I want at dinner. The pounds started coming off and I'm approaching my ideal race weight for the first time since high school.
Also, I found that quasi-fasting during the work week allows me to eat what I want on the weekend, which tends to be the time I go out for food more often.
As for fasting and running, I simply make sure to have my lunch about an hour before running and have a light snack after my run. This prevents any sugar-low from occuring.
Because of how much I like to eat, there's no danger of losing too much weight. In fact, after 3 years of trying, I've yet to hit my exact ideal weight, but I can usually get within several pounds of it by racing season, which is good enough. I'd rather err on the higher side of the ideal race weight.
Posted by: Monica Reinagel | Feb 25, 2008 1:10:09 PM
Kate,
Just to be clear, the type of modified fasting we're discussing here is:
1. intended as a weight loss strategy for those who are legitamately overweight.
2. not done for more than one day in a row. On the off day, you eat the normal amount (or even a bit more).
3. still involves eating 600 to 1000 calories during a "fasting" day.
Most people on this regimen will find it most comfortable to eat a little bit at regular intervals throughout the day.
If you're feeling "shaky," then I wouldn't recommend a strenuous work-out. If you're just slightly hungry but you feel otherwise well, you should be ok to work out. I think you really have to listen to your body.
Posted by: Monica Reinagel | Feb 25, 2008 12:56:22 PM
Laura,
one argument is that because you alternate low and normal intake, the body does NOT adjust to the lower caloric intake the way it would if you reduced calories every day. I don't think that's been scientifically determined.
But this is primarily a weight loss strategy. Once you're at your goal weight, you'd want to eat the number of calories required to maintain that weight, which you can calculate using the Daily Needs Calculator. Obviously, if you eat more than that, you will gain weight.
A while ago I remember reading about a guy who found that fasting one day a week and not worrying about what he ate on other days allowed him to maintain his ideal weight long-term without "dieting."
Posted by: Kate | Feb 25, 2008 12:02:48 PM
What about exercise on your fasting days? I sometimes get a little shakey when I don't eat for a long time. Is it dangerous to do my regular workout of 3-5 mile run + weight-lifting on the days when I fast?
Posted by: Laura | Feb 25, 2008 11:24:37 AM
What are the long-term effects of this? In order to be effective and maintain your goal weight once you've reached it using this strategy, does this have to be a permanent lifestyle change? Or can you return to an every day eating pattern and not regain the lost weight? It seems to me if someone has established a routine of eating only 20-30% of their normal caloric intake every other day for several months, the body would adjust, so that when the faster returns to a normal eating pattern (s)he would pack on the weight again.
Posted by: Joe | Feb 18, 2008 12:39:05 AM
I am a 240 lb. 43 male. Last year my peak weight was 270. I have been fasting three days a week for about two and a half of the last twelve months. Sticking to my diet only 25% of the last year may not sound great but I have always had a terrible track record with diets (and I've tried them all) because of my absolute love of foods. This is the first one I can at least stick to for a few weeks at a time. I juice veggies on my fast days and that has really boosted my immune system. I was sick all the time before, now I don't get sick even if my wife and co-workers have a contagious flu. I highly recomend fasting.
Posted by: Dyan Buffa | Feb 17, 2008 8:10:02 PM
I have been doing intermittent fasting since February 2006. I went from 206 pounds to 140 pounds. I am a big cheerleader for intermittent fasting. Now I do 20 hour of fasting and a 4 hour window of eating everyday.
I don't know if this will work for everyone, but it does work for me. It makes life easier just having to worry about eating one meal a day. Also I seem to just naturally make better food choices and have more energy then I have ever had in my life. Want to go running with me?
Just my one rat study results. Each person has to make their own decisions about what is right for them.
Posted by: Monica Reinagel | Feb 15, 2008 10:39:00 AM
Another great question! As I mentioned in my post, you always want to choose on nutrient dense foods when you fast--no empty calories. But with restricted calories, you might still not be getting the DV for every nutrient.
Going an entire day without eating will not cause nutrient deficiencies. So, in that sense, the Daily Values are just a guideline for average intake, not requirements for every 24-hour period.
The goal would be for your intake of nutrients over two days to be roughly twice the DV. With a nutritious diet, I think that would be easily doable.
ND can help: For example, you could customize your individual daily values to 200% of the recommended DVs(see "preferences" under "tools") and then track your total consumption for two days to see if you hit your targets.
But for people doing modified fasting over the period of several weeks, a multi-vitamin might be a good insuance policy.
Posted by: Anastasia | Feb 15, 2008 8:51:27 AM
Setting the calories aside, what happens with the nutrients when you fast? I mean, suppose you consume a 2-day doze of, say, calcium or some vitamin in one sitting, and the next day go without it altogether, will your body still get the necessary amount? Are those Daily Values called so because you actually have to eat them every day, or just for convenience?
Posted by: Monica Reinagel | Feb 14, 2008 2:16:04 PM
Veronica,
You're right, of course. Small, short-term studies can only be considered preliminary.
The effects of fasting on diabetics have been well-studied in the Muslim community, where the traditional observance of Ramadan involves 30 days of modified fasting (no food until after sun-down).
The reports seem to indicate that fasting is not not harmful for Type II diabetics who are overweight--in fact, it appears to be helpful. Type I diabetics or poorly controlled Type II diabetics should fast only under a doctor's supervision. Blood sugar levels during and after fasting need to be closely monitored and medications such as insulin or hypoglycemic agents may need to be adjusted. Fasting would not be advisable for people with hypoglycemia.
To be on the safe side, if you have any medical condition requiring treatment, you should check with your doctor before experimenting with modified fasting.
