Dr. Mosley Please Write a Revised Fast Diet using 800 Cals Per Day!

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Dr. Mosley Please Write a Revised Fast Diet using 800 Cals Per Day!

This topic contains 21 replies, has 11 voices, and was last updated by  Coffeebrained 6 years, 7 months ago.

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  • I hope this message gets through to Dr. Mosley.

    As I stated elsewhere on this forum, I am very excited to return to 5:2 using 800 cals per day. About 3 or 4 years ago I lost 7 lbs. in a month doing 5:2 500 cals per fasting day…but it was just not sustainable. I was STARVING on 500 calories. Now I have experimented with eating 800 cals in a day, and I can’t believe the difference a mere 300 calories can make! Now, I can’t do this every day like in Dr. Mosley’s 8 Week Blood Sugar Book, but I can do this twice a week!

    Yes, I know the topic of 5:2 on 800 cals was briefly discussed in that book, but let’s face it, the book was not focused on 5:2 fasting. We need a revised Fast Diet book with new guidelines, tips for fasting days, etc. A book whose sole purpose is 5:2 fasting. I just purchased Jacqueline Whitehart’s new 5:2 book that has the updated 800 calorie guidelines plus extra guidelines on fasting hours. Dr. Mosley WE NEED A NEW BOOK FROM YOU, THE MASTER!

    That is all. Carry on!

    Hi Sheryl-joie, My guess is that Dr. M. is writing that new book at the moment, or at least I’m assuming he is doing so. In any case, my sense is that we’ll be hearing more about this.

    From the interviews I’ve read in which Dr. Mosley speaks of raising the 5:2 calorie count, that he’s recommending 700 calories for women and 800 for men, which means an extra 200 calories over the original protocol.

    I see the prospect of 700/800 calories has generated a lot of interest from those who found 500/600 calories not doable, so it is good to see that so many have returned.

    Hi Minka, thank you for answering. It would be wonderful if he is revising his Fast Diet book. I know it seems silly to get excited over an extra 300 calories a day, but because of that, I feel I have found a way of eating that is sustainable that I can do for the long term, not just another diet that I give up.

    Here’s hoping he is indeed refocusing the Fast Diet book. I am on a 5:2 Facebook group, and a lot of people are upping their calories to 800 per fasting day and breathing a sigh of relief, because this is something that is entirely doable. Who cares if the weight loss slows down? Slow and steady wins the race!

    Fingers crossed that we get a new book this year! Have a nice day.

    Also, it’s my understanding that the 800 calories is for both men and women, at least that’s what he stated in his 8 Week Blood Sugar book.

    Hi Sheryl joie,

    Below is a link to the interviews with Dr. Mosley that you can read yourself, in which he explains that 5:2 revision which to me clearly states a 200 calorie increase from the original protocol.

    Yes, the Blood Sugar Diet allows 800 calories, though those 800 calories are meant to be eaten every day for 8 weeks.

    Women consuming 800 calories on FDs only may make intermittent fasting more doable though may take longer to achieve weight loss results. If it is a whole group that has decided to raise their consumption to 800 calories, well, it is up to each of us or collectively as a group. However, if following Dr. Mosley’s research and findings, he states that his recommended intermittent fasting calories are 700 for women and 800 for men on fasting days. Here’s the excerpt from the interview in which he clearly states that and find the actual link following…

    “You don’t need to stick to 600 calories. Cutting down to 800 calories a day seems to be almost as effective and for some people much more ‘doable’.”

    “It’s low calorie, without being superlow-calorie. And if you want to have lunch, you can slip those extra 200 calories in there.”

    Note that Dr. Mosley himself is a male. He speaks for himself that he consumes an extra 200 calories on fasting days which raises his total fast day calories from 600 to 800. The newspaper then extrapolated that everyone can now eat 800 calories because those who wrote the article never read the book or practiced 5:2 so don’t realize that women were only afforded 500 calories in Dr. Mosley’s Fastdiet book, so it is really a false headline and misleading article. Men have always been allowed a higher fast day calorie count. As you read above, Dr. Mosley speaks of adding an extra 200 calories to his own regime which brings the tally from 600 to 800 and I did hear him speak of this when being interviewed by a male Australian journalist who was also on a fasting day at the time. Below is the excerpt from Dr. Mosley’s interview that draws me to conclude that the new revision means adding in an extra 200 calories for men which equates to 800 calories for each fast day and 700 for women.

    “You don’t need to stick to 600 calories. Cutting down to 800 calories a day seems to be almost as effective and for some people much more ‘doable’.”

    “It’s low calorie, without being superlow-calorie. And if you want to have lunch, you can slip those extra 200 calories in there.”

    He told the Mail on Sunday: “If you are going to have lunch, have something like a nice bowl of hearty soup, or grilled fish and a decent pile of vegetables or salad.”

    I read it as adding in an extra 200 calories. It is the newspaper that concluded that everyone is plentifully afforded 800 calories whether male or female.

    FDs. This whole announcement of 800 calories in the headline just wreaks of inaccurate misleading journalism. What else is new, Lol! Anyway, that’s my two cents and it really doesn’t apply to me since I focus on sticking to eating 25% of my TDEE on my fasting days which has worked for me.

    Here’s the link…


    Also note Dr. Mosley’s sentiment that it ‘seems to be’ ‘almost as effective’, so the jury is out as far as I’m concerned.

    Here’s another forum discussion about the same that point out some interesting aspects of the revised 5:2 version


    I read that it is 800 for both men and women – and have just restarted 5:2 for the very reason it has gone up to that amount! Have completed 2 fasts already and have a feeling this time round will be successful! Interested to hear more on this.

    There was no science behind the value 500/600 calories on a “fast day”. It was just a number that Mosley thought most people could handle rather than a complete fast which people seem to struggle with. I suppose if more people attempt to do 5:2 as a result of upping the value to 800 then that’s a good thing. Personally I find it easier to go with zero on my fast days rather than fuss about what to eat. To each their own I suppose.

    Minka, actually, I have Dr. Mosley’s book The 8 Week Blood Sugar Diet where he talks about 5:2 as an alternative, and he definitely suggests a solid 800 calories two days a week for everyone.

    So, I’m going with what I read in the book, written by Dr. Mosley himself, instead of web interviews, which sometimes get it wrong.

    Whatever we follow, here’s to weight loss for all of us!

    Maryanne, I just read your post, and I feel the same way! Isn’t it amazing how an extra 300 calories on fasting days can make all the difference? We can do this.

    I’m a past 500 FDieter who found it very difficult to stick to for any length of time. Maybe my age, 65 and having an underactive thyroid, is the reason why I fall by the wayside. My daughter who is 37 has been on the 5:2 for almost a year and is almost where she wants her weight to be, so I know it does work.

    So I’ve just begun on the 800 for two days/week and it seems to be much more doable. However, by doing the 800 do we need to lower our TDEE calories on the NFDs?

    I’d be interested to hear what others think.

    The original 500/600 calories was 25% of TDEE for average woman/man (whoever they might be….) rather than an arbitrary figure.
    Whether anyone decides on 700 or 800 calories for a revised version of 5:2 is a personal decision but the fact is that weight loss will be slower than traditional 5:2 which is probably why Michael says “almost as effective” but if it means that someone is able to stick to it that is better than aiming to eat 500/600 calories and failing.

    Femme Anglaise, your TDEE is what it is according to your statistics but IMO it would make sense to eat 100 calories less on non fast days to compensate for the increase on FDs and you might be able to lose 1lb per week.

    From what I’m reading in these forums, the 500 calorie Fast plan works slowly for most people, maybe a pound per week. I would think that going up 200 or 300 calories would make it even slower. I need to see at least a pound per week to stay motivated.

    Hi All. I also Have the book The 8 weeks Blood Sugar Diet. Dr Mosley says 800 calories for every day but only for 8 weeks based on Med. Diet (stage 1) to reverse type 2 diabetes. Also, losing weight fast has better result and then the maintaining phase (stage 2) is up to dieter if they want to continue with 5:2 800 cls or 6:1 800 calories(when they reached the target) and for the rest of the life (stage 3) stick to the Med. diet. it means low carbs, high protein and fiber.

    This is my understanding. Please correct me if I’ve got it wrong.

    The 5:2 800 cls is a slower style of losing weight and size (especially on waste-line) but people who have already diabetes type 2 less than 10 years they would have advised to start with 800 cls 7 days for 8 weeks under doctors’ provision.

    My weight loss is slow enough on two 500 calorie FD. Granted, I’m not always super careful on NFD and rarely count calories on those days, only FD. For me, that’s doable. FD aren’t too hard because it’s only twice a week. My weight loss is just over a pound per week. I would be less motivated to stick to it if the loss was even slower.

    In the end, it all boils down to calories. The 5:2 is an effective way to reduce them overall without have to count every day. Calorie usage and rate of burn may be imprecise, but overall that’s what causes weight loss.

    800 is 25% of my TDEE (I’m big). But I stick to 600.

    Shouldn’t changing the diet from 600 to 800 simply mean scaling up the food you eat by about 33%?

    For me 600/day is more effective than water fasts because I can easily do 3 600/day fasts per week for a 7800 calorie cut, which is more calories than I would cut with 2 water fasts (6400).

    I would really, really struggle to do more than 2 water fasts in a week. I also find that sticking to 600/day teaches me to be more mindful of how much I need to eat, what sort of foods can be satisfying without a lot of calories, and plenty more benefits.

    Well, I wish that Dr Mosley would make this point clear for all soon if dieters can switch to the 800 cls without making any interference into the weight loss process.

    I had stopped fasting for a while. Now I would try 5:2 800 calories Mediterranean diet to see how it works on my waistline size.
    Best of luck to all 🙂

    Hi everyone! Like a lot of folks, I am now doing 5:2 at 800 calories, and it is finally sustainable.

    Until Dr. M writes his updated Fast Diet, which I agree with someone above who said he would, I am reading a book I heard about through another Fast Fiver, The New 5:2 Cookbook by Jacqueline Whitehart. She goes over all the new 5:2 updates, including overnight fasting, a companion to 5:2. This author said she couldn’t stick to the old 5:2, and I couldn’t either. Until we (hopefully) get Dr. M’s new book, this one is a must, in my opinion.

    The 800 calories is for everyone, man and woman. Here’s a link going around different 5:2 groups that explains it: http://www.telegraph.co.uk/news/2017/03/12/good-news-dieters-52-relaxes-rules-allows-800-calories-day/

    I’d love to read updates from anyone who is practicing 5:2 and consuming 800 calories on fasting days. So far, I’ve yet to read of anyone who has stuck with it for at least 6 months and reported results. For example, how much weight are you shedding per week on the 800 calorie 5:2 plan? Are you continuing to find it as easy as described in some of the posts above? Thanks.

    Minka, there are older posts on this forum, back when Dr. Mosley did his “which diet is for you” documentary, with people having success on the 800 calories.

    Also, Dr. M only “officially” updated the 5:2 revision in his March 2017 interview with The Telegraph, although he did briefly mention it in his 2016 book The 8 Week Blood Sugar Diet. I am hoping he gives further clarification soon, since so many people seem confused/concerned. I honestly don’t understand the concern though. He basically explained it all in his interview.

    It’s working for me whereas 500 calories were not sustainable. I’m losing about a pound a week, whereas on 500 calories I lost a little over 1 1/2 pounds a week, but I just couldn’t stick to the 500 calories. Too hungry!

    One thing I’ve realized which nobody even mentions, is that the original 2 day diet study by Dr. Harvie, used between 650 to 1000 calories on diet days, averaging around 800 calories, and the clinical study shows they lost weight.

    All I know is, I can finally stick to 5:2.

    I’ve just been browsing through the active topics and came across this one about upping the 2 FAST DAY calories to 800.

    I’ve tried the 500 5:2 and failed miserably. I upped my calories to 800 5 weeks ago, and am pleased to tell you all that I have lost TWO pounds, just shy of ONE kg, EVERY WEEK.

    It’s so much more realistic and I have had no problem sticking to 800 calories. To compensate for the extra calories I have reduced my TDEE, which was 1800, to 1500 on NFDS.

    My weekly calorie consumption works out as follows:

    FDs 1600
    NFDs 7500
    Total 9100

    An average of 1300 CALORIES/DAY

    I do not do a huge amount of exercise, but enjoy a good brisk walk, and I do a 15 minute yoga routine each morning, oh and my two granddaughters keep me active! I am 65 and have hypothyroidism which has played havoc with my metabolism, but even so doing the 800 DEFINITELY WORKS.

    Give it a try.

    I’m doing 800 calories a day, but I don’t count calories on my nonfast days. I guess we all have to find what works for us. I agree 800 is more realistic and definitely works. I should add I’m no youngster, so if I can do this, anyone can!

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