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Talk to Michael Mosley about Intermittent Fasting, Wednesday 23 January, 12pm - 1pm.

166 replies

RachelMumsnet · 21/01/2013 13:10

On Wednesday at 12pm midday Michael Mosley will be joining us for a webchat and to answer questions on Intermittent Fasting (also known as 5:2 diet).

Michael is a medical Journalist whose BBC Horizon Programme in August last year first introduced the UK to Intermittent Fasting. His latest book The Fast Diet presents the science behind the diet, whilst his co-author, Mimi Spencer explains the practicalities and how to go about it. The idea behind Fast Dieting is that you eat normally for five days and then then consume just 500 calories (women) and 600 calories (men) on two fasting days each week.

If you're interested in finding out more, join Michael Mosley on Wednesday 23 January at 12 midday or post a question to Michael in advance here.

Mumsnet Academy is now offering you the chance to join 5:2 The Fast Diet Course with Michael Mosley, a one day course in Central London on Friday 15 February. Book your tickets

OP posts:
mintycake · 23/01/2013 12:08

Hi Michael
Can you tell me is it better to fast consecutive days or space them out? Also does it matter what makes up the 500cals on fast days?

MichaelMosley · 23/01/2013 12:09


Ok I am starting today, I have put 4 stone on following an emergency complete hysterectomy and the following early menapause as a result.

I cannot really exercise much at the moment as I am in pain a lot and waiting for more surgery. I have a very high rate of cancer in my family so am interested in the benefits of this.

What I would like to know about are any side effects both long and short term and how long before I can expect decent weight loss.

The only known side effect is that you will get hungry and won't be able to stick to it. The first few weeks can be tough so good to join a support group. To be properly evaluated need long term trials, but i would add that all the great religions advocate fasting and have done so for centuries without any serious suggestion that it is harmful. I personally never go for more than 12 hours without food. Water, lots of it, is essential
virginposter · 23/01/2013 12:09

Hi Dr M

Does 6:1 have the same health benefits as 5:2 and did you have your IGF-1 levels checked whilst doing 6:1.
Many thanks for changing my life :)

MichaelMosley · 23/01/2013 12:10


Why is this WOE unsuitable for type2 diabetics and should you reduce Metformin dosage on fast days?

I think that people are rightly cautious about type2 diabetics and fear of going hypo. If you are thinking of you should discuss with your doctor
phlebas · 23/01/2013 12:14

I've been doing IF since last summer (after the Horizon programme), in that time I've lost 21kg & have 17kg to go to get to my goal weight.

My question is about maintenance - is it better (for health) to sick with 5:2 or change to 6:1? How do you manage not to lose more weight?

MichaelMosley · 23/01/2013 12:16


Hello Dr Mosley, thanks so much for finally stopping by. :) As you and your researchers know, we're big fans of your work over on the 5:2 threads.

are there any studies regarding differences in the way male and female bodies react to this diet?

Also, are we to assume that on non-fast days, we should be eating approximately our TDEE allowance? Obviously we all have different definitions of "eat what you want", as that's how we gained excess weight in the first place!

I really appreciate you taking the time to answer our questions. Thanks For myself, I've probably lost 18 pounds since August, and I'm extremely pleased with that. Christmas, for the first time in a very long time, was not riddled with guilt over what I "should" or should not be eating!

Most of the studies so far have been done with women, overweight but premenopausal. The benefits seen in women (compared to a standard low calorie dietg) include losing more weight, being able to stick to and reduced inflammatory markers (important for things like breast cancer and asthma).

There is some evidence that men find it easier to exercise in the fasted state, and burn more fat, but not seen studies that say if the same is true one way or the other with women.

I believe that one reason this approach works is because our bodies were forged in a climate of feast or famine. It would be strange if women never went hungry in the past
Huggy1234 · 23/01/2013 12:18

As this is relatively new, how can we be sure of the long term benefits?

NigellaPleaseComeDineWithMe · 23/01/2013 12:19

Started to do this with DW a few months ago - seems to be the easiest 'diet' to do. PLus with busy lives doing 5:2 we make sure the 2 days are on busy days when we take kids to activities etc so don't have time to eat. Does seem to make sense as I think it's all too easy to eat more than the recommended amount daily so having 2 days off helps to balance this out.

No question really - just think it's a simple idea plus like the idea of the longer term health benefits.

MichaelMosley · 23/01/2013 12:20

This reply has been deleted

Message withdrawn at poster's request.

MichaelMosley · 23/01/2013 12:22


Hello dr Mosley
I watched the horizon programme and have read the book and I think it sounds great.
I am finding it very hard to have only 500 cals on fast days.
I also find it hard when I am on my period.
Do you have any tips for making the fast easier to do? Time wise etc.
Is there aypnything I can do to assuage my pmt/hormone related binging?
Thanks! :)

The first few weeks are the toughest, and it is a good idea to join a support group, like ones you will find here on Mumsnet or facebook. I have a website, which is also quite active. This is a very democratic movement and hugely self supporting.
The reason for 500 calories is that was the figure the scientists have researched. There is nothing magic about it. If 600 works better for you, fine. The main thing is those calories should be satisfying, satiating and nutrient rich. Loads of recipes around online, in our book The Fast Diet, etc etc
Badvoc · 23/01/2013 12:25

Thank you!
Will definitely be trying again.
I have already lost a stone by fasting so I know it works.
I will check out the website, thanks again.

MichaelMosley · 23/01/2013 12:25

Some people have asked what regime i am currently on. Well i did 5:2 until i had dropped to my target weight, 12 stone. My wife, a GP, then said i was looking too gaunt so i switched to what i call 6:1. I do my 600 calorie thing once a week and a few days a week skip lunch. That way 2-3 times a week i go for 12 hour periods without food. Haven't had my bloods retested yet but feel fantastic on it

Salbertina · 23/01/2013 12:27

Just wanted to say thanks for answering my message directly. So appreciative of how you've brought this mainstream. Will public health messages catch up??

AntiDiet · 23/01/2013 12:28

Can someone tell me how I actually get on this webchat? Or am I on it and just nothing is happening? Sorry- first time doing this. Really interested to learn about this.

BIWI · 23/01/2013 12:28

You're on it, AntiDiet!

duchesse · 23/01/2013 12:29

You're on it AntiDiet! You just need to do the same thing again and ask your question.

MichaelMosley · 23/01/2013 12:30


Hi Michael
Can you tell me is it better to fast consecutive days or space them out? Also does it matter what makes up the 500cals on fast days?

I started out doing Mondays and Thursday because it suits my life. Some people prefer consecutive days. Does it matter? No-one knows. These days, as i mentioned before, i'm largely doing 1 day a week and skipping lunch. Will check my bloods and see how they are doing. If glucose and cholesterol up will revert to 5:2. In terms of dementia risk first human trials due to start soon
LizzC · 23/01/2013 12:30

Hi Michael, Unfortunately I missed the Horizon programme (and didn't know there was a book out either - think I must have had my head in the sand!). Is there anywhere I can watch this episode, and you could also let me know what the book is called please. Many thanks LizzC

AntiDiet · 23/01/2013 12:31

I have also heard the above (from WeShouldOpenABar) about 8 hours stretches. Surely this can't work!

AntiDiet · 23/01/2013 12:32

Thank you! DOH!

MichaelMosley · 23/01/2013 12:32

The biggest changes i have seen in myself, apart from significant weight loss and improvements in biochemistry, is my attitude to hunger and to vegetables. I used to snack as soon as i felt a pang, these days i just let it go. I knew veg was good for me, but used it as a garnish. Now i pile my plate. Someone contacted me via my twitter account, @drmichaelmosley the other day to say she had eaten veg for the first time in her life and enjoyed it!!

LizzC · 23/01/2013 12:33

I was the same AntiDiet you are not alone! her her makes me feel more human!

SeriousStuff · 23/01/2013 12:33

LizzC try this

MichaelMosley · 23/01/2013 12:36


Hi Michael, Unfortunately I missed the Horizon programme (and didn't know there was a book out either - think I must have had my head in the sand!). Is there anywhere I can watch this episode, and you could also let me know what the book is called please. Many thanks LizzC

The book is called The Fast Diet; i should add there are a number of others out there called some variation on The 5:2 Diet, written by people who have little or no science training, simply saw my prog and copied it. I've read a couple of these books and they were not good.I have higher hopes for Dr Michelle Harvie's new book though not seen it yet
LizzC · 23/01/2013 12:36

SeriousStuff - Great, thank you

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