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Re: What are the 'rules' of 5:2 fasting?

PostPosted: 17 Jan 2013, 15:59
by polsonby
Dr M said he tries to maximise the length of time without eating anything on both fast days and normal days - so 12 hours between breakfast and dinner. He said he skips lunch on normal days too. Grazing keeps your blood sugar high so your body is constantly exposed to insulin which is one of the factors in developing type 2 diabetes. The fasting is intended to reduce the blood sugar for long enough to let your insulin drop. I think there is a good bit in the book about this. Anyway - the gaps between food are really important and 12 hour gaps seem to be good

Re: What are the 'rules' of 5:2 fasting?

PostPosted: 18 Jan 2013, 15:00
by Pashcaline
On Feeding days I eat either 10-15% over and some 10-15% under my 2000cal. Is it ok for health and Weight loss in a long term? Xx

Re: What are the 'rules' of 5:2 fasting?

PostPosted: 18 Jan 2013, 15:05
by carorees
Sure! Eating normally would usually involve varying how much you have each day. As long as on average you are consuming under what your body needs you will lose weight. The health benefits are largely due to the weight loss and the other (as yet unproven) benefits come from reducing calorie intake dramatically a few times a week.

Re: What are the 'rules' of 5:2 fasting?

PostPosted: 18 Jan 2013, 16:33
by Dean
carorees wrote: .... in the section on how to do the diet Mimi does suggest that the restricted calories could last for 24 hours only, so 2pm one day to 2pm the next for example.

However, it seems that most people (we should do a poll on this perhaps) do the 36 hour option of eating no more than 500/600 cals between dinner on day 1 to breakfast on day 3.

I would suggest that weight loss will be faster doing this than just 24 hours and the other health benefits are likely to be better. However, as mentioned, sustainability is vital so you need to work out what is best for your circumstances!


Yes I would agree, I think Mimis got that wrong about the 2pm till 2pm. Thats an idea from the Brad Pilon "Eat Stop Eat" regime where he eats nothing at all for 24 hours.

Re: What are the 'rules' of 5:2 fasting?

PostPosted: 23 Jan 2013, 09:26
by 1625
I have read the eat stop eat book. Brad started studying IF in 2006. His belief is that you are either in the fed state or fasted state. As soon as you eat you are no longer fasting even if your calorie intake is low. Even milk in your tea takes you out of the fasted state. He believes you get health benefits from being in a fasted state for longer, optimally 24 hours. He suggests not eating for 24 hours, taking in no calories at all! A way to do this is to eat your meal in the evening on day 1 then not consuming any calories till the same time the next day, eating a normal meal. If you break up your fast by spreading out your 500 cals, surely you are taking yourself out of the fasted state. I think you will not get the health benefits? Isn't it more like calorie restriction than fasting? Obviously you will still get weight loss benefits.
I highly recommend Brad Pilon as a source of information on the science behind fasting.

Re: What are the 'rules' of 5:2 fasting?

PostPosted: 23 Jan 2013, 10:18
by carorees
Dr M says that Krista Varady is doing a study on this at the moment.

Even if it is true that fasting 24 hours before your 500/600 cals is more beneficial, sustainability is the most important thing. So if people struggle with doing that, it's better that they find a way to have a very low calorie day (i.e. spread the calories out) than to give up. As this regime leads to weight loss, which is the biggest health risk, any way that enables people to lose weight and keep it off is a good thing.

Having said that, I notice that many people who start off spreading their calories, end up saving them till dinner and so doing a 24 hours, or thereabouts, fast - which is what I do.

Re: What are the 'rules' of 5:2 fasting?

PostPosted: 23 Jan 2013, 10:22
by 1625
Yes, I think you feel more satisfied at the end of a 24 hour fast if you have a decent healthy (approx 500 cal) meal and go to bed without feeling hungry.

Re: What are the 'rules' of 5:2 fasting?

PostPosted: 23 Jan 2013, 10:26
by dominic
@1625: oh dear, are we not even allowed milk while fasting? The food fasting I can manage, but doing without milk (or a substitute, though I haven't found one I like yet) in my tea and coffee through the day might be the final straw...

Re: What are the 'rules' of 5:2 fasting?

PostPosted: 23 Jan 2013, 10:38
by PhilT
dominic wrote: @1625: oh dear, are we not even allowed milk while fasting? The food fasting I can manage, but doing without milk (or a substitute, though I haven't found one I like yet) in my tea and coffee through the day might be the final straw...


GenesisUK's 5:2 diet protocol was very milky http://www.genesisuk.org/downloads/pdf/ ... f45ee3.pdf

Re: What are the 'rules' of 5:2 fasting?

PostPosted: 23 Jan 2013, 10:46
by carorees
Personally I think that was a big weakness in the study! As we have previously discussed, milk promotes IGF-1, and so to base the fasting day meal around that is probably not a good idea! Probably it was some off-the-shelf meal replacement formula!

Dominic, please remember that while these scientific debates are very interesting, the MOST important thing, is to find a sustainable way of losing and keeping the weight off, so if that means having some milk in your tea, then of course, have the milk in your tea!

As yet we don't know what the "best" fasting regime is or how much of an impact varying that regime would have.

Re: What are the 'rules' of 5:2 fasting?

PostPosted: 23 Jan 2013, 11:34
by PhilT
carorees wrote: Personally I think that was a big weakness in the study! As we have previously discussed, milk promotes IGF-1, and so to base the fasting day meal around that is probably not a good idea! Probably it was some off-the-shelf meal replacement formula!

It was just milk. AS you say, the study didn't demonstrate any statistically significant difference in health parameters between the two approaches, but both achieved significant reductions in several health parameters compared to baseline http://www.ncbi.nlm.nih.gov/pmc/article ... /table/T5/

the key message appeared to be that IF is as effective as continuous calorie restriction and that the weight loss delivered the benefit, not the IF.

Re: What are the 'rules' of 5:2 fasting?

PostPosted: 23 Jan 2013, 18:16
by dominic
Very interesting link, thanks PhilT. This 2011 UK study found that neither 5:2 fasting nor continuous calorie restriction reduced IGF-1, but as you have pointed out, the 5:2 dieters were instructed to drink 2 pints of semi-skimmed milk on fasting days, and semi-skimmed milk promotes IGF-1 just as much as full milk, so I agree with carorees that this really makes this part of the study's results meaningless.

I couldn't find the reference in the text to your suggestion that the benefits were all down to weight loss and none down to any other effects? Indeed they say at the end that 'our data is suggestive that periods of severe restriction may have different effects which may be important in the long term for disease prevention.'

They also say 'recent reviews speculate that [intermittent fasting] may be associated with greater disease prevention than [continuous calorie restriction] due to increased cellular stress resistance... The tendency for greater improvements in oxidative stress markers in our [5:2 test group] than in the [continuous calorie restriction test] group may support these assertions.'

This all seems to me consistent with the 5:2 lifestyle offering real health benefits aside from any weight loss, although it does not prove it.

@carorees: thanks for your observations about milk! I'm not going to get too upset about small amounts of milk in tea and coffee. If the test group in this survey could drink 2 pints of milk on fast days and not see increases in their IGF-1, I think a few drops can't do me too much harm...

Re: What are the 'rules' of 5:2 fasting?

PostPosted: 25 Jan 2013, 19:16
by Kizzia
BruceE wrote: I'm somewhere in the middle of the 24 and 36 hour category, where I eat right up until bed time the day before a fast (last food, say, 9:00-10:00p.m.) and the 600 calorie limit goes until breakfast (about 7:00-8:00 a.m.) the day after -- so about 32-35 hours or so.

I was wondering if it might be good to take advantage of an unanticipated lack of appetite the morning after a fast (I go to bed quite hungry, wake up not all that hungry) by waiting until late morning or even noon-ish to eat, adding another 2-4 hours to the fasting time.


Hi BruceE

I have managed to do exactly this as you say I do not feel hungry first thing - I have never been a breakfast person.

I have so far managed to go from dinner on day 1 to lunch on day 3, which is getting towards 40 hours with 500 cal!

I drink lots more on fast days and noticed that today I was thirsty so I am pleased I felt the need to drink more water (not my most favourite beverage) even when it is not a fast day so this is making my fast last longer.

Good luck K x

Re: What are the 'rules' of 5:2 fasting?

PostPosted: 25 Jan 2013, 22:01
by allic
I've only done 2 fast days so far, but I have noticed that on the days after the fast, although I wake up thinking - yippee, I can eat now! - I actually don't end up eating til after about 1-2pm, which makes my fast closer to 43 hours. It's not a deliberate thing, just how it has panned out so far, who knows what will happen next time?
alli

Re: What are the 'rules' of 5:2 fasting?

PostPosted: 25 Jan 2013, 23:40
by PhilT
"I couldn't find the reference in the text to your suggestion that the benefits were all down to weight loss and none down to any other effects?"

there were no statistically significant differences in disease markers and other parameters between the two groups, but both groups experienced statistically significant reductions relative to baseline. So we're left with either calorie restriction as the cause, or the weight loss, and no way to split them out as you can't have a calorie restriction without a weight loss.

Harvie has published elsewhere the benefits of weight loss of breast cancer risk.