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Fasting / 5:2 diet

Talk about intermittent fasting and 5:2, including what’s worked for others. Mumsnet hasn't checked the qualifications of anyone posting here. You may wish to speak to a medical professional before starting any diet.

5:2 thread 104: Here's to FAST-ening those jeans!!

406 replies

harriethoyle · 10/03/2026 19:38

Welcome to the continuing thread for those following 5:2 or other forms of IF (Intermittent Fasting) such as 4:3, ADF, etc.

Basically it is 2 very low cal days ("fasts") per week - which need not be consecutive - and eat "normally" to maintain on the other 5 days.
For those who have dieted or maybe overeaten for years, eating "normally"
means roughly the number of calories your body needs to maintain - NOT reduce - its weight (see TDEE calculator below).

IMPORTANT
If you have had past diagnosed Eating Disorders or serious MH problems you should NOT do 5:2 or any other kind of fasting.

JARGON alert
16:8 is a different type of fasting, which can be combined with 5:2.
Daily zero-cal fast for 16 hours and eat within an 8 hour window. To lose weight, this needs a weekly calorie deficit as well
b2b (optional) back-to-back / consecutive fast days, each with an increased allowance of 650 calories instead of 500
BMI (Body Mass Index) healthy range is 18.5 - 24.9 for Caucasians. Upper limit may be 22 for some of Asian origin.
FD = single Fast Day: aim for 500 calories (600 for men or 25% TDEE whichever is higher) or 1000 cals for BF
No alcohol or junk on FDs
Even if you exercise strenuously, do NOT increase FD cals to allow for exercise
MFP = My Fitness Pal, a useful App or website to track food & drink calories
miniFD = MiniFD, tel:850-1000 850-1000 calories, no alcohol or junk
NFD = Non-Fast Day, averages around TDEE
NSV / LSV = Non Scale Victory / LifeStyle (change) Victory, e.g. compliment, smaller waist, clothes size
SV = Scale Victory
TDEE = Total Daily Energy Expenditure, the average number of calories you burn in a day, is calculated from your current weight, height, age, activity level.
Aim to average about this for NFDs.
WOE / WOL = Way Of Eating / Way Of Life. We say this instead of "diet", to emphasise that we must make a permanent change in how we eat, to maintain our new healthy weight long term.

Jump in and say hello!!

OP posts:
harriethoyle · 10/08/2026 08:58

Anyone with me today? Day 1 of a b2b…

OP posts:
mumofbun · 10/08/2026 10:10

I'm in today, already a struggle though as i'm so hungry...

harriethoyle · 10/08/2026 13:47

Same @mumofbun I had to steal a (mini) pack of biscuits from the work kitchen for an 11am hit😂I slept appallingly last night and it's really not helping...

OP posts:
mumofbun · 10/08/2026 15:32

harriethoyle · 10/08/2026 13:47

Same @mumofbun I had to steal a (mini) pack of biscuits from the work kitchen for an 11am hit😂I slept appallingly last night and it's really not helping...

I went to the vending machine for a boost 😂

harriethoyle · 10/08/2026 18:28

Kitchen closing on 774. How did you get on @mumofbun ? x

OP posts:
mumofbun · 10/08/2026 20:58

harriethoyle · 10/08/2026 18:28

Kitchen closing on 774. How did you get on @mumofbun ? x

It all went to pot as we hadn't planned dinner and ended up being invited for a roast ... Try again tomorrow! I did speed walk across town for Pilates though!

harriethoyle · 11/08/2026 07:51

I love a roast @mumofbun - totally irresistible! The IF will have helped, no doubt.

Im back for day 2 of 2… wish me luck!

OP posts:
harriethoyle · 11/08/2026 18:30

Kitchen closing on 924 - higher than intended but I felt positively weak at 10.45! So a colleague gave me his biscuits 🤣

Going to Dishoom for a curry tomorrow night so definitely back on Thursday for day 3..!!

OP posts:
harriethoyle · 13/08/2026 10:06

Signing in for day 3 after a positively gluttonous night out last night... BUT IT WAS SO GOOD 😂

OP posts:
harriethoyle · 13/08/2026 20:48

Kitchen closing on 689 😊

OP posts:
midnights92 · 16/08/2026 23:45

Back at it tomorrow for the first time in about a year of pregnancy and newborn stage to lose about 3st of the 4st I gained while pregnant. I'm EBF so going to be doing 2 x minis per week instead of proper FDs and see how it goes. Never really stopped doing 16:8 because it had just become a habit, so hopefully that will make the transition easier.

Hope everyone is doing well!

harriethoyle · 17/08/2026 07:25

Welcome back @midnights92 !

Im fasting today then on holiday with friends until next Monday so only one day this week. Will try and keep the activity levels up to compensate!

OP posts:
HLBug · 17/08/2026 19:07

Kids are back to school - whoop whoop!!
BUT I have a shocking week at work and an interview on Thursday for another role…. so I’m stressed 😩 and when I’m stressed I EAT.
I’m being kind to myself and aiming for 2 or maybe 3 minis this week. Kitchen closing today at around 1087

HLBug · 31/08/2026 15:38

Checking in for a Mini - anyone with me?

harriethoyle · 31/08/2026 18:39

Back tomorrow @HLBug - see anyone who’s fasting here!

OP posts:
harriethoyle · 01/09/2026 08:37

Signing in for first FD in two weeks 😬 not expecting it to be easy!

OP posts:
HLBug · 01/09/2026 12:19

I’m here today as well @harriethoyle.

closed yesterday at 755 which was better than I was expecting

today looking closer to 840 due to me already having eaten my lunch Blush

harriethoyle · 01/09/2026 12:26

I am SO HUNGRY @HLBug 😂Going into a meeting now otherwise I would be inhaling my teeny tiny FD sandwich. Had forgotten how brutal a first day back could be!

OP posts:
harriethoyle · 01/09/2026 18:49

Kitchen closing on 725 which I’m happy enough with - today was hard! Back on Thursday for day 2 and I will try and be virtuous tomorrow 😊

OP posts:
harriethoyle · 02/09/2026 07:21

Aiming for a mini today after a delicious breakfast 🤤 then back tomorrow for a FD. Satisfying reduction on the scales this morning too!

OP posts:
harriethoyle · 03/09/2026 10:51

second FD of the week - poor planning on my part means I am WFH which I always find makes it far harder. Hiding in my office away from the fridge 😂

OP posts:
harriethoyle · 03/09/2026 21:02

Kitchen closing on 662. Happy with that!

OP posts:
harriethoyle · 07/09/2026 08:26

Oooof. Heavy weekend 🙈 and it’s reflected on the scales! FD today and tomorrow to undo the damage. Who’s with me?

OP posts:
harriethoyle · 07/09/2026 18:16

Kitchen closing on 740. Back tomorrow.

OP posts:
HLBug · 07/09/2026 19:22

well done @harriethoyle- I’m finishing on 851 over here!
the last few weeks I’ve been doing 3 x minis in a row, which I’ve found a lot more manageable tbh.
not weighed myself in a good wee while though… will wait and do that next week due to being on my period at the moment which will be impacting things.
I’ve committed to doing Sober September which should hopefully help reset things about summer

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