I have been on the 5:2 at 500 calories since July 2018 and have lost a stone at a steady pound a week – I wasn’t particularly overweight at the start but just felt I would feel better if I could reduce my weight – I clearly had stone to shift! I am 4 pounds of my goal weight having managed a holiday and Xmas which I stabilised at the same weight for a month or so. The 800 calorie allowance sounds fabulous when I have been managing on 500! I am slightly concerned though that the weight will increase having got so used to 500! I eat healthily so it hasn’t been a big change to the core of my meals, but my indulgences are bread, cheese, crisps and wine so there has clearly been a lot less of that!

I can see an 800 calorie FD working for someone doing 5:2 either for the health benefits or to maintain weight.
Whether it works as a serious weight loss tool really depends a persons TDEE. I’m sure that for those with a TDEE over 2000 calories will still get steady weight loss with 800cal FDs. There are however plenty of people on this site with TDEEs below that and quite a few below 1600 calories (mostly women). Doing 2 x 800cal FDs would result in unbearably slow weight loss and I think would result in some people giving up because the progress was just too slow.

Good points from L Joyce. I am 5’3″, so TDEE is 1440 or so. I lost two stone on 5:2 in 2016, but confess that I usually went a bit over, more like 550 cals.

I have maintained on daily 16:8 since. Basically eating what I like – luckily I’ve lost my appetite for sugary stuff and have a considerably reduced appetite anyway. I do think OH woukd benefit from a short, sharp shock of daily 800, though. He’s procrastinated long enough.

Yes a good point my TDEE is 1600 so the increase from from 500 to 800 Cals on two days must have a slower impact. I am going to stick with 500 at least until my goal has been met!

I tend to be an emotional eater for spans of time and because of this, 1/4 TDEE fast days are essential. I’m working on finding ways of living a life of greater wisdom and poise than ‘stress response eating’ and do succeed at this too, though until I completely do that, 1/4 TDEE is an essential and winning strategy for me and I happily continue with it. I do wish I were able to see Dr. Mosley on the tour, though it doesn’t include Australian venues so I will wait for now!

Dr. Mosley, I should have added I will be 66 years old this year, yet I am now losing at the same rate as in my 20’s…and on 800 calories twice a week! I think this is because although I don’t follow your Med diet, my own plan is close enough, limiting sugar and focusing on fiber too. I agree with what you say in your book, that you just shouldn’t go beserk 5 days a week. Those days matter too. I think that is why the new 800 cals works so well. Please tour the U.S. too!

If we do the 800 kcal a day diet my worry is when we retun to eating more kcal will our metabolisms slow and weight increase? Will there also be a rebound increase in appetite ie fighting against the set point?

@delayedgratification,
The set point theory has not been proved, and it is likely it isn’t true at all. Instead it seems that many people put weight back on after weight loss because they go back to their old habits.
Losing weight rapidly helps people with their motivation, so that is to the good.

However, if you are worried about it, skip straight to doing 5:2. If you can make it sustainable you can do it for the rest of your life (that is what I am doing).

Good luck with it.

Hi my first post but I’ve been doing 5:2 since May 14th 2018. I’m a 53 year old women and as of today have lost almost 70lbs. I love this W.O.E. Now that I just read about the Fast 800 I think that might be a great way for me to maintain. I’m excited to try this.

Thank you Dr Mosley for an interesting and informative read. It is good to see that some of the health benefits attributed to intermittent fasting, besides weight loss, have now been established through rigorous scientific studies. That is reassuring, and encourages me to continue with this way of eating.

A bit about me: I’m a 58 year old female, 5’7.5″ and started 5:2 about 14 months ago, when I was about 200lb. I just followed the recommendations in the original book, without any major modifications to my usual diet or eating times/ patterns. I have been experimenting more with recipes though, so my diet now more closely resembles a Mediterranean diet – but it’s a long way from perfect! It took me 11 months to shed 50lb, or put another way, 25% of my body weight, to reach my target of 150lb. In the beginning I was losing about 2lb per week, but this soon tailed off to average 1lb per week. I feel and look better, and my recent NHS health check was green (healthy) across the board. Since reaching my target, I have been aiming for 800 calories on fast days, and have been fasting, on average, about once per week (allowing for holidays and a recent heavy cold).

Some of the findings in ‘the fast 800’ surprised me, for example, that rapid weight loss is a good thing- I’d always thought ‘slow and steady’ was the best way to lose weight (that’s how I did it). It’s also interesting to see that time-restricted eating has been proved to be beneficial. This is something I will be trying out from now on.

What I would really like to know now is, how to convince a sceptical world that this method really works? As has been expressed in the book, I too find it extremely frustrating that there seems to be an unwillingness to take this new research seriously – I guess because there’s no money to be made from it. I have spoken to a few medical people recently and told them about my success. They have all offered their congratulations and some have asked questions from a personal perspective (I guess because they are interested in trying it for themselves), but beyond that I wouldn’t know how to engage them. I suggested to the nurse conducting my health check that I could talk to the GPs in my surgery about 5:2, but this was not followed up (I guess they are just too busy). If I look to my GP’s website for weight loss advice, I’m directed towards the well-known commercial companies that hold classes in my area. I wish I knew how to spread the word! I’m willing to speak if anyone is willing to listen!

Hi,Do Ketones affect the brain in a negative way.I am 3 weeks into the Fast800 have lost 8Kg from 90Kg,however have a problem with blurring vision/dizziness mainly after getting up from sitting position or lying after exercising I normally surf and sup (stand up paddleboard)but being cautious at the moment pluss bike swim stretch so a fair bit really for someone with two hip transplants and one knee transplant. due to complications from exercising post knee op last year I stopped pretty much everything and put on 6kg from 86Kg.I had a history of high blood pressure so on pills for that, went to see doctor thinking that may need to reduce pills as I have lost weight and my B/P is down from average 140/76 to 122/67 and causing the problems. He told me it was the ketones that were affecting my brain and I needed to eat more, the problem came again one day after I had done an 18hr fast so perhaps he is onto it but I hav,nt noticed this effect in any stuff iv read so far.He also wants me to see a nutritionist but im not keen as fear they maybe too old school in their outlook and set me back.I stand at 168cm (5.5ft) my BMR is 1601 my average (moderate/very active) tdee 2165 im 62yrs,has anyone else come up with any problems such as mine.Cheers Gus.

I started on the 5:2 diet in October 2016 and I lost 10kg in 8 months. I am pleased with this because, when I stray a bit from the diet, I do not put much weight back on – at least not so far (touch wood)!

What is tricky right now is that my blood pressure (BP) has come down so much that I feel dizzy quite frequently. After decades of taking BP tablets for high BP, my GP has finally acted by taking me off one BP medication (Zanidip) and I am measuring my BP every 2nd day. It’s still on the low side and I still get some dizzy spells. Hopefully, my GP will take me off the other BP tablets (Micardis) soon. Then I’ll be free of BP tablets for the first time for 40 years! Thank you 5:2.

Being an old researcher myself, I am wondering if there’s been any research done on the precise relationship between the 5:2 diet and blood pressure? Perhaps Michael could elaborate on this relationship?

Thrdage,
A controlled day isn’t part of the original program.
Some people choose to do some of their NFDs (non fast days) as controlled days. This is where we aim to eat fewer calories than our TDEE. Some people can lose weight easily on 5:2 without this but others struggle. I struggled because I have quite a low TDEE so I had to be quite careful with my eating on NFDs too if I wanted a steady rate of weight loss.
If you are doing 5:2 mostly for health benefits then the controlled days should not be necessary.

Started 5:2 a week ago. I have a pretty comprehensive exercise program on Tues. & Thur. afternoons. Which would be the best days for me to fast while accommodating the exercise program?

Many thanks for this is a great help. I have incorporated the 16:8 as well just because of force of habit throughout the week. Is this still okay to do this: FD 9on a Tuesday and Thursday and my other 5 Fay’s I don’t start eating until 12pm next day as I stopped eating at 8pm the night before.

Many thanks

Hi – I have just start the 5/2 diet. I have high hopes of results having read The Fast Diet book. I would appreciate support as it must help in the initial weeks. Do the fasting days always have to be the same? My weekly routine can vary.

On your none fast days, should I be sticking to 2000kcals and eating really healthy or should I be eating healthy on all my days to lose weight but not necessarily counting calories . Many thanks

I have recently came off a fasting style diet and have had some amazing results.
here a some links that may prove helpful.

https://weightlosssecrets.video.blog/
https://www.healthline.com/nutrition/6-ways-to-do-intermittent-fasting

Do what ever days suit you. This flexibility is why 5:2 works. If I’m out for a meal I enjoy myself, without being stupid or moaning that my ‘on a diet’. I adjust my fast days to balance it.

It’s my three year anniversary today 😄. Just took five months to reach target.

Dear Dr Mosely,

Thank you for your update – very informative and useful to know the benefits of initial rapid weight loss..

Thank you, thank you, thank you so much for all your work in spreading the message on how to healithly lose weight and combat the detrimental results of modern lifestyles.

Thank you, also, for this forum that helps so many people, and me, by providing us with a welcoming, supportive and informative community. It is an essential part of the process for so many of us.

Personally your work in explaining and publicising Intermittant Fasting, 5:2, and now Fast 800, has changed my life radically. The follow on ripple effect through my family is creating healthy changes also.

I’m 68, female, started 5:2 in Nov 2014, with Myalgic Encephalomyelitis (Chronic Fatigue Syndrome) of 16years following a severe viral episode that had a catastrophic result. I had gone from hyperative (ADHD), very fit and strong, 47 yrs old with a physical age if 37, in 3 days, to bedridden, damaged language, loss of all maths, long and short term memory damage, no diurnal ryhthm, ‘thermostat’ damage, various other bits of damage and only producing energy at 5% of normal with loss of an energy ‘store’ to call on. Recovery included 2 yrs in bed. As a result I put on 30kgs, which adversely impacted my health, including my heart.

Now, it is 21yrs following the virus, 21 yrs of ME/CFS, and 4 1/2 yrs of 5:2. That 4 1/2 years has co-incided with a couple of stretches of significant stress from several life stresses occuring simultaneously. During those times I continued trying to do 5:2 and time restriction of no calories before 12 noon, as I am in the Hunger Dragon group. I on a private trial of a drug being researched which is helping my body produce more energy – 1 1/2 years and continuing.

I started 5:2 in Nov 2014 at 83kgs, 169cm(5’6”) with trepidation, after taking 6yrs to lose 10kgs making all the changes I could, then not able to go further. In Nov 2016, after 2 yrs on 5:2, I reached my goal of 62kgs, still in the sedintary category of exercise. I would love to do HIIT but can’t, but I encourage others to do 10,000 steps/day and to do HIIT). I would do them if I could. With energy level at 35% of normal, my heart went back to better functioning, off blood pressure meds, and my GP was very impressed and congratulatory. My cardiologist said no need to have yearly checks, and very happy with the result. The medication trial has lifted my energy to 55% of normal now.

With some significant life stress still happening I have been continuing the battle with stress eating of carbs, sugar, over-eating when tired, sabotaging my FDs, and slow creep of weight which recently saw me at 67.8kgs – 5.8kgs above my goal weight and getting quite worried. I started 800 a day 4 days ago, again with trepidation, not knowing if my body could handle it. 5:2 had not affected my ME/CFS adversely at all, so I was hopeful.

StartIng at 67.3kgs on Monday with 1 good FD, and 4 x 800 days, today I’m 66.1kgs – a loss of 1.2kgs in 5 days. I’ve found the 800 days easy to do, and credit my experience with 5:2 for making it easier to adjust. The daily and rapid weight loss is motivating and produces both positive self-talk and strengthens my response against stress. No adverse ME/CFS response so far. I’m comfortably looking ahead now to getting back to my goal weight.

Re 500 or 800 on a FD, my choice is 500. Being in the sedintary category and unable to exercise at any length or speed, my TDEE is approx 1400, and for me, 800 on FDs would be too slow a loss. As my goal weight got cliser I had to keep my FD calories at 1/4 TDEE to keep the loss going steadily, and had settled at 365/ FD. In maintenance I was able to do 365-500 on 2 FDs/week, eating in time restriction on 5 non-FDs/week, not eating till after 12 noon. FDs I have 1 meal after 6pm.

Thank you once again Dr Mosely!
Merry,
Australia

For those looking to gain a physiological understanding of how intermittent fasting works and all the benefits associated with it, I recommend watching this video: https://www.youtube.com/watch?v=suJ_L49NBbU

Hi Pixels – thank you. Today and the future are much brighter thanks to Dr Mosely, 5.2 and everyone on the forum.

Hi,

I had blurry, misty-like vision, and a feeling of being ‘spaced-out’ whilst restricting food intake (‘fasting’). As soon as I ate a small bag of fries it went away and I felt much better. I had eaten healthy carbs (carrot batons) which didn’t help me feel better… so there just wasn’t enough carb content in carrots as in fries … or perhaps I could have just eaten some cheese for the fat, and perhaps that would have restored my sense of reality! Anyway, it wouldn’t surprise me if lots of fasters were topping up with non-recommended foods. Perhaps some people find the programme manageable and effective as they are more disciplined and motivated to achieve their weight-loss goals.