On-Off Fasting: Does It Work?
The study, of 12 women and 4 men, all obese, was led by Dr. Krista A. Varady and colleagues at the University of Illinois at Chicago. It has been published in the American Journal of Clinical Nutrition as Short-term modified alternate-day fasting: a novel dietary strategy for weight loss and cardioprotection in obese adults.
As the title indicates, this sort of diet is a "novel" one - not something that dieters normally consider, or that doctors normally recommend. The participants in the study were instructed to eat normally on their "feed" days, and to eat just 25% of their maintenance calories between 12pm and 2pm on their "fast" days.
On average, participants lost around 12 lbs in eight weeks. They also saw other health benefits: the New York Times explained that:
At the end of the eight-week diet, their total cholesterol had dropped by 21 percent, on average, while their LDL cholesterol had dropped 25 percent. Moreover, their systolic blood pressure (the upper number in a blood pressure reading) had fallen by an average of five points.
The participants ate around 100-125% of their maintenance calories on "feed" days, so did not overcompensate for the "fast" days. Dr Varady suggested to the New York Times that their stomachs "kind of shrunk", so they were satisfied with less food.
Should we all be fasting to lose weight?
It's important to note that this was an extremely small study - just sixteen people - and so the results are not necessarily representative. Also, the individuals involved were all obese (BMI over 30), so if you have less weight than that to lose, this sort of diet could be inappropriate.
On-off fasting may well work for some people, but don't try it without consulting your doctor first.
(Image above by laffy4k)
I have done one-day fasts occasionally (religious) and I've always found it's a lot easier to stay away from all food for a day than to try to cut my portions. Basically, you're cutting calories, but instead of cutting your calories in half every day, you cut out all your calories every other day ... I might think going with something like every third day might have similar benefits, but be a little easier to manage. Reply
I know someone that does this & swears by & it & has the results both physically & doctor wise to prove it. I don't know enough about it & not sure I would do it. Will have to read more about it.Reply
I can get pretty cranky when I'm hungry. Not sure how I would function at work and with my children on those fast days. Reply
I wonder how similar this is to eating "warrior style", where you eat 100% of your calories at once and then just don't eat the rest of the day. In a sense, that's almost the same thing...you're fasting for almost 24 hours and then eating again. I've eaten warrior-style before and it's odd because you don't get hungry between your "meals". When I ate that way, my LDL numbers and blood pressure numbers were excellent, so maybe there is something to the whole intermittent fasting thing.
If you think about it, most animals are intermittent fasters. They eat when they can and sometimes go one or two days with no food. Reply
I've done this type of fasting and the way I've done it is you never go a full day without food. You eat dinner at 7pm then don't eat until 7pm the next day. I found that not only did I not get hungry when not eating, I didn't get cranky or sleepy or jittery, my blood sugar didn't get wacky and I really felt quite energetic.
I agree with Spectra, animals are intermittent eaters. Some wild animals will go days without food between kills. Where did the idea come from that we humans have to eat 3 meals a day??Reply
Flo, that's very similar to the "warrior" method I was talking about. You do eat every day but you go 24 hours between meals. The trick is to make sure your meal is full of very nutritious foods, not just ice cream and pizza. Because I've known people that eat only once a day...they go all day with no food and then binge on crap at night. Those are the stereotypical people that are the ones that "shouldn't eat at night" or whatever. Reply
I'm guessing that the 3 a day came from a farming type community lifestyle. I've worked on farms, it's a long hard day, and three meals makes sense. Of course if Taco Bell had their way, and they probably do, there's a fourth meal :-(Reply
I can't even skip breakfast without scruffling down a gigantic meal at dinner. I guess it varies from person to person. For me, this definitely wouldn't work.Reply
I've eaten "warrior" style, for a while. I got into doing it because of the limited time factor with being a surgeon. Like Spectra said, I'm not hungry even though I go 20 hours or so between meals. Of course, I stay busy :-)
I don't recommend this to people, mainly because most can't do it, and it doesn't fit the SAD way of living. That said, after getting used to it, it works pretty well. Like many eating styles, the body adapts to them. Consistency is key. Reply
Fasting is very hard for me, I tried it a couple of times but have never been successful, I always do better by just eating smaller meals through out the day.Reply
I think you gotta do what works, but in my experience fasting is a bad idea. Hormones have so much to do with weight loss / gain and if we let our blood sugars get to low it not only affects your mood, or can have you shakey, but will set you up to over eat faster than the speeed of light. If over eating isn'tbad enough, when you get that hungry you're likely to eat the wrong foods as well. Weight loss is all about keeping your blood sugar levels steady, keeping active and most importantly, consistancy with both! Weight loss should not be about suffering and I don't believe fasting will have long term affects, so why suffer through it? Reply
Occasional fasting is probably very healthy. It improves your insulin sensitivity.
There is a study with Mormons, comparing those who fast once a month for religious reason to those who did not. They are a good study population since confounding factors such as smoking and drinking are absent. Those that fasted had a lower risk of cardiovascular disease and diabetes.
http://www.ncbi.nlm.nih.gov/pubmed/18805103Reply
This is the basis of the Johnson Up Day Down Day diet (JUDDD). Supposedly it helps with inflammation diseases too.Reply