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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!!

143 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:
Buntyforgirls · 18/04/2026 07:21

Thanks for all the tips and advice everyone.
And woop on the losses. I lost 2 pounds this week- planning a sensible weekend so that they are not back by Monday.
Have a lovely weekend everyone!

TeaRose29 · 18/04/2026 10:15

Thanks @harriethoyle for the gin recommendation - I’ve been put off the AF spirits by the high prices and the fear that they won’t taste of anything!

harriethoyle · 20/04/2026 08:08

Morning all - checking in for first FD of the week. I am doing b2b today and tomorrow and might squeeze a third in on Thursday... we will see!

Lentil soup for lunch and a naked burrito (Lidl; in the freezer aisle, genuinely tasty and 349 calories for evenings when you want something easy) with a pile of broccoli.

OP posts:
harriethoyle · 20/04/2026 19:36

Kitchen closing on 543 - back tomorrow for day 2 when I have a princely 757 to play with. Living the dream! 🤣

OP posts:
harriethoyle · 21/04/2026 09:45

Good morning! Signing in for my b2b. Anyone with me?

Ham sandwich for lunch and ramen soup for tea. Should come in around 750 if I go light on the noodles.

OP posts:
mumofbun · 21/04/2026 10:33

I have a fitness class this evening so not going too hard today. Planning a FD for tomorrow!

harriethoyle · 21/04/2026 17:56

Kitchen closing on 775 making an almost perfect 1318 for my b2b! 😇

back here on Thursday I think, cannot wait for breakfast tomorrow but have a gym session first thing. Will feast when I’m back 🤣

OP posts:
mumofbun · 22/04/2026 08:17

FD today for me

On my second coffee already...

Have a very sad looking weetabix for lunch. Banana, apple and some crisps (😮) for during the day. And then we have some chicken marinating to have with brocolli tonight.

harriethoyle · 22/04/2026 13:25

I love weetabix @mumofbun but I have it with butter and marmite which no one else I know does 🤣

OP posts:
mumofbun · 22/04/2026 15:16

harriethoyle · 22/04/2026 13:25

I love weetabix @mumofbun but I have it with butter and marmite which no one else I know does 🤣

I've literally never heard of anyone doing that haha! My husband did forget his milk and have to eat it dry once though...

harriethoyle · 22/04/2026 15:26

It's delicious @mumofbun - if I hadn't been at the gym this morning and SO ravenous when I got back I grabbed yoghurt because I couldn't bear to prep anything, I had it planned for my post FD breakfast. It can be Friday's brekkie instead!

OP posts:
harriethoyle · 23/04/2026 11:33

Trying for a FD today but it's been hard so far... WFH which always makes it more challenging. Soup for lunch and fishcake and broccoli for tea if I can stick to it...

OP posts:
TeaRose29 · 23/04/2026 14:23

Protein mini (and over 15k steps) yesterday and weighed in at 9.13 3/4 this morning, so I’m officially back on the 9s now, yay!

Tried THE jeans on again yesterday and they are almost comfortable now. Stay strong @harriethoyle! 💪💪

harriethoyle · 23/04/2026 18:50

Kitchen closing on 684 which feels heroic! 🤣

OP posts:
Buntyforgirls · 23/04/2026 21:39

Well done @harriethoyle , that is very impressive.
I had a hard day yesterday, and bailed.
Easier day today, so going for 800 tomorrow

HLBug · Yesterday 22:15

Had one of those weeks and decided to cut my losses. Feeling much better after a calm family day today, and will be back on it tomorrow for a Monday / Tuesday B2B.

mumofbun · Today 22:14

751 today, wasn't too bad but had one snack extra! I have a headache though - anyone else getting them on FDs?

HLBug · Today 23:07

Finishing on 718 over here.
Is it every FD you come down with a headache @mumofbun? That must be frustrating. Have you tried putting some electrolytes in your water / salt on your meals? How is your sleep? My top FD tip is to go for a lunchtime nap! I WFH once a week, a Monday, and it saves me from eating lunch…! Cup of tea when I wake up and then back to work.

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