Should we have a monthly fast day?

06 Nov

Modern day weightlosers and health seekers are bombarded with loads and loads of diets. Before we had to wait until this years nutty diet hit  the book stands. These days, because of the internet, a  diet regime can be up and running in minutes.

One of the interesting ideas that is currently floating about is an  intermittent fasting go a day without food.

So, here is the task. Can we conclude that this is safe to recommend and layout guidelines for those who want to have  ago, and is there any evidence that an occassional fast does any good at all?

So my 1st swipe at this was

1) it may be a good idea to have  a practise at going  a day without food and see how you go. This isnt based on any diet ideas, merely the observation that its all too possible to get stuck in a mini crisis ( during the oil blockade a few years ago some shops started looking quite sparse: during the recent snow, some got stuck in their cars overnight). In short it appeals to the hidden geek survivalist in me: (could I make snares out of wool in my jumper and 2 pens… etc.)  We have fire drills at work: maybe we should have hunger drills

2) the rest of the world frequently goes without food for a day. Whats it like?

3) many religions mention  and make use of fast.

4) it is being touted as  a diet in certain sites



Who ought not to ?

If  we are to produce the ultimate fasting guide, we probably need to suggest that people taking medication should consult their doctors. Sally pointed out that lactating mothers probably shouldnt. Id add to this airline pilots,  merchant bankers who could buy billions of pounds worth of toxic debt at the flick of a drowsy finger could beware , people who are driving? Who else I wonder?


Nothing to eat does not mean nothing past the lips

katatina produced a very interesting talk about the effect of hydration on performance which she gave  at the last runners clinic. You must drink water


The problem with fasting is that it could be associated with abusive eating habits. Does lack of food mean you will eat your own muscle, will you binge at the end of the fast, will you get drowsy and fall over??


So, what can you do?

We need to find what science exists, what experiences people have, and what advice is out there. ( and if its science or speculation).So post away

But here are a few  participation observation/rules. At this stage, we need to get the basic information in. Im not overly anxious to start detailed critique of the sources here. We will do that when everything is collected.  It will help  if when  you find blogs/ reports – dont just blanket paste website details – see if you can summarise the thrust of the argument as well.

Assuming we can put some literature together, we may see if we can get some volunteers together to give it a go and get some blood tests done?



20 thoughts on “Should we have a monthly fast day?

  1. a 36-h fast significantly altered substrate utilization at rest and throughout exercise to exhaustion, 2) glucose levels do not appear to be the single determinant of time to exhaustion in submaximal exercise, and 3) despite the apparent sparing of carbohydrate utilization with the 36-h fast, endurance performance was significantly decreased. appl Physiol. 1990 Nov;69(5):1849-55.
    Effects of a 36-hour fast on human endurance and substrate utilization.
    Zinker BA, Britz K, Brooks GA. 7 men cycling at 50% of 1 rep max

  2. i need to hold of these

    Halberg N, Henriksen M, Soderhamn N, et al. Effect of intermittent fasting and refeeding on insulin action in healthy men. J Appl Physiol 2005;99:2128–36.

    2. Chakravarthy MV, Booth FW. Eating, exercise, and “thrifty” genotypes: connecting the dots toward an evolutionary understanding of modern chronic diseases. J Appl Physiol 2004;96:3–10.

  3. I get headaches after 3 hours without food so no I won’t be fasting..

    Can you read the papers cited above and tell us what it says?.. Too lazy..

  4. I’m thinking that choosing a day when everyone can do it together could be problematic. For the reasons given above, fasting makes you vulnerable – so which is the better choice: a weekday or weekend?

    Personally, I wouldn’t like to endure a Sunday at home starving, with a full fridge not 10 feet away. I’d rather be distracted by work: safe in the knowledge that if I feel a bit woozy, hundreds of magazine readers won’t die.

  5. That should have read “depleted” not “deprived” important distinction methinks…

  6. Muslims on Ramadan and Jewish people on Yom Kippur etc don’t drink water when they are fasting. If the goal is to replicate the religious fasting experience or truly see the effects of fasting to empathise with those less fortunate, allowing yourself to drink water completely defeats the purpose.

    Looking at it from a testing standpoint, I would question whether just doing a one off one day fast and getting bloods done or looking at how you perform in the gym that day is scientifically that sensible. Any number of things could have happened that day or the preceeding one to skew the test. If it was me, I’d try it out for a month but with smaller fasts (ie 12-16 hour without eating) and then you’d have some more conclusive data or try it once a week (no food) for a period of time.

    I’d be interested to see some of the science behind people recommending it for performance reasons. Or if anyone had good experiences with it etc?

    1. @Pat/Andrew – I fast every year for Yom Kippur i.e. no food and water for 25 hours. For the purposes of health and well-being, there is nothing at all to be gained by going without water for a day. Dehydration kicks in far earlier than you would expect i.e. long before you feel thirsty. It is the lack of water, rather than food that leaves you feeling rough all day (and you do feel rough all day). You would be incredibly foolish to try and train during the middle of this.

      In my fasting experience (which I do every day between 20:00 and 12:00) going without food is very easy – as long as you keep hydrated. The more you allow dehydration to be factor (VERY easy in air conditioned offices) the harder it becomes. The mind often confuses dehydration with hunger.

      If you have a diet rich in carbohydrate (grains, starchy veg, sweeties, etc.) fasting is also far harder; the blood sugar spikes and dips play havoc with the body’s natural satiety signals, often telling you that you are hungry (ravenous, low on fuel, empty tank feeling) when this is not really the case at all. I suffered from this for years until I switched the majority of my food intake to a more paleo friendly approach.

      Again, in my personal experience, a 30 hour fast (food only) is comfortably doable; hunger signals really only kick in at scheduled eating times which is a psychological conditioning rather than a fueling issue.

      And finally – because I haven’t seen anyone say this explicitly yet – DO NOT TRAIN FASTED until you have at least a few months experience with fasting. I have done it a few times over the past couple of years and my experiences have gone from “surprisingly great” to “my world is ending” bad.

  7. Hi all, I have experimented with less than 24 hour fasts, and training fasted.

    By fasted I mean either eating dinner then not eating breakfast and training in the morning/lunch time (saturday morning crossfit) or skipping breakfast on a weekday and eating a very late (paleo) lunch then training brazilian jiujitsu 6-8 oclock, then having dinner.

    I cant report ever having felt gassed or hungry or feint on these occasions. I have experienced cramping during sparring, which I interpretted as a mineral deficiency (remedy with some lightly salted lemon-water).

    Also can report a very keen sense of energy and focus while and after training fasted, usually carries on until I eat and then things ettle.

    This has generally been while on a paleo diet, with lots of fat.

    Hope this anecdotal evidence helps!

  8. great ideas pat. ( and well done efe, chris temi veronika et al for your info: all invaluable)


    American Journal of Clinical Nutrition, Vol 48, 1197-1210,
    “Body weight loss and changes in blood lipid levels in normal men on hypocaloric diets during Ramadan fasting”
    MH Hallak and MZ Nomani

    . “By the end of Ramadan, body weight, blood TGs, and high-density lipoprotein cholesterol (HDL-chol) had decreased significantly (p less than 0.05), low-density lipoprotein cholesterol (LDL-chol) had increased, and total cholesterol had not changed compared with base-line values.” yet to read it all

    BTW, Phil Rolling dropped me an email, and he is rapidly assembling the results of some of the stuff he has looked at and client experiences.

    also have been sent copies of Eat stop eat, and Berardi’s “experiments with intermittent fasting”

  9. Alternate-day fasting in nonobese subjects: effects on body weight, body composition, and energy metabolism

    “Leonie K Heilbronn, Steven R Smith, Corby K Martin, Stephen D Anton and Eric Ravussin”

    Conclusions: Alternate-day fasting was feasible in nonobese subjects, and fat oxidation increased. However, hunger on fasting days did not decrease, perhaps indicating the unlikelihood of continuing this diet for extended periods of time. Adding one small meal on a fasting day may make this approach to dietary restriction more acceptable.

  10. I’ve been doing the Eat-Stop-Eat thing off and on for a couple of years now. I haven’t actually read that book, but have done it based on advice from a guy called Larry Lindenman on a self-defence forum. One of the reasons I started was that, due to a chaotic work schedule, I could miss meals without suffering. I then had a go at the ‘eat every three hours’ bodybuilding style approach when I was trying to put on muscle. It worked, but I found that if I missed a meal, I felt awful. One benefit I’ve found is that I’m back to not needing to shovel stuff into my mouth every few hours.

    When I want to drop some body fat, I have two 20+ hour fasts a week. This can be eat dinner, then nothing until dinner the next day, or the same for breakfast etc. I find it gets easier as the weeks go on. Lindenman reckons he’s happy weight training while fasted with the addition of BCAA’s, but I tend to set things up so that I break my fast by drinking protein/carb shake from just before my session.

    I used this method when I was training for a triathlon. Combined with a much-reduced volume of strength training, and a frankly terrible diet rich in refined carbs, I lost about 8kg – a mixture of fat and muscle. I did some of the shorter workouts fasted, and didn’t notice any ill effects, although my performance might have been affected – impossible to tell with a sample of one.

    My job can involve me needing to perform physically, but again I’ve not noticed any issues. I make sure I have a protein bar or even just a chocolate bar available just in case, but I’ve never felt the need. Andrew’s mention of the study showing that it’s not just carb deficit that can affect performance should be interesting to read, as I’ve always operated on the assumption that I’ve probably got a good hour and a half of intense exercise’ worth of carbs in me. Lindenman noticed that he can’t go much more than this in intense BJJ rolling without ‘bonking’. What I’ve read about central-governor stuff and the study showing the effect of mouth swilling carbs is borne out in my experience of how quickly icky feelings disappear upon eating something.

    My personal belief – based on no knowledge whatsoever – is that most of the ill effects people experience with the shorter-term fasts are just the brain telling you it doesn’t like you messing with its routine, so I’ll be interested in seeing what actual science shows is really happening.

    I’ve heard that there are supposed other benefits of intermittent fasting, but I’ve only really approached it from the calorie-control point of view. In line with that, I also take the view that if I’ve over-indulged one night, I’ll miss a couple of meals the next day, or just have some protein, I might pre-empt a planned binge the same way. I realise that some people (my girlfriend, who’s psychology degree focus was on eating disorders, for example) think it’s a bad thing to miss meals, but I figure that if the overall calorie count for the week is the same as if I’d just cut back on each meal, what’s the difference? The only caveat is that you have to avoid stuffing in a whole load of extra calories when you do break the fast, as that kind of defeats the purpose.

    Sorry if this was more ramble than science, but I thought you might be interested in opposite-of-expert-lazy-joe’s experiences with fasting.

  11. I’ve just undergone 36 hours of forced fasting due to food poisoning. Not to go into too much detail but after spending a glorious 15 hours emptying my body of all traces of food/water I understand better the importance of hydration. If you do go down the fasting path then definitely keep the water intake up.
    I’m a litre of h2o into my recovery – all hail the water gods!

  12. I ate £20 worth of accorted chocolate and taytos on sunday, I like the idea of prefasting for the binge.

  13. Intermittent Fasting in the mainstream media:

    It’s from a presentation at the American Association for the Advancement of Science. The researcher proposes that reducing your daily intake to less than 500 kcal twice a week can stave off degenerative brain diseases. He reckons that that it puts brain cells under stress analogous to exercise with muscle cells and causes new neurons to be created. Next up: MRI scans to determine effects of fasting.

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