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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.

One 24 hour fast a week has helped where 5:2 did not

112 replies

Lemonthyme · 08/04/2026 11:16

I have a good diet, being sober and exercising a lot, perimenopause was starting to cause weight gain. With some levels of change to my diet to cut out the crap, this changed to stability (which would and did cause loss when I was younger). There was one thing though that pushed me into trying something different and that was my HbA1c result which was 5.8%. So despite doing EVERYTHING the NHS tells you to do to be a healthy weight, I was still overweight and very close to prediabetic (other countries would already class this as prediabetic).

I've not had another HbA1c result back since I started once a week 24 hour fasting on top of everything else I've done but what is changing is I'm losing weight. Total weight loss is c. 1-1.5 lbs a week so not huge but consistent and enough that it's really starting to be noticeable.

I have been so fed up since perimenopause hit with things not working. I'm really pleased something is and it kind of makes sense that if there's good evidence that intermittent fasting works to improve insulin resistance, if IR was my problem, that would have been making it harder to lose weight so it is a complete lightbulb moment for me that it's probably been that.

As for "how" as that's what I would have been wanting to know. I "read" an audiobook on the science behind the hormones of weight loss and it advocated one 24 hour fast a week (or possibly two) for insulin resistance and metabolic flexibility as your body has to switch to burning fat. Two sounded terrifying but one sounded possible. They then went onto explain that all you do is finish eating dinner on, say Monday at 6pm then miss breakfast and lunch the next day, eating dinner on Tuesday at c. 6pm or later. Well that sounded less frightening even though that is 24 hours, it's actually only missing 2 meals. I'd originally thought about doing it just once a fortnight but when I tried it, realised that it was easy enough (it only gets a little harder from 4pm onwards) and if anything I now almost look forward to my fasting days. What's more is if I'm busy with work, it's actually easier.

I'd previously tried 5/2 though and didn't lose an ounce. So I wanted to share this with people in case you've tried one form of "IF" type approaches and assumed they all didn't work for you (although I'm not really sure if 5/2 is really IF).

Top tips I have is to have herbal or spice (not fruit) teas so they're calorie free, black coffee and plenty of sparkling water. I don't personally have any sweeteners anyway but I think most people avoid them when fasting. Also if you find you're struggling and exercise a lot like I do, sodium can be depleted by fasting so another tip is to have some electrolytes or even a pinch of salt (e.g. in coffee) if you're struggling.

I genuinely cannot imagine stopping doing this now unless I'm advised to medically. It's far easier than any other method I've used to try and lose weight. I'm a total convert.

OP posts:
JumpLeadsForTwo · 29/04/2026 19:50

BIWI · 29/04/2026 11:25

Why do you need to tell them specifically what you're doing? Just say you've been on a diet!

If they press for more info, make sure you have enough knowledge to describe intermittent fasting and its benefits - weight loss being just one of them. (Autophagy is a good place to start)

I think I have very nosey female friends/ work colleagues who are also perimenopausal and wanting to lose weight without resorting to WLIs. I think I’ll be more confident telling them about this when I have lost more weight and I’m more confident it will continue working until I’m in the ‘healthy’ bmi range 😂

zanahoria · 30/04/2026 09:18

Lemonthyme · 29/04/2026 10:05

I have to admit that's the reason why I don't go beyond 24 hours. The thought of going to bed hungry is not a good one. And also there's been no need. 24 hours is working so far. At my heaviest I was 13 stone 6 I think. Through sheer grit and determination I got down to 13 stone 1-2 over the period of months. Now, fasting once a week I'm at 11 stone 12 (weighed this morning).

I have 2lbs to lose to then officially be no longer "overweight" and, ideally, 1 stone 12 to lose to get to what I'd term my ideal weight. (Which would be a BMI of 21.3.)

I genuinely don't know if this would work for everyone but I also don't know why everyone wouldn't try it. It's been a revelation for me.

I do understand why people are sceptical, eating disorders are prevalent in our society and horror stories about them are way more prevalent than success stories about responsible fasting.

I believe that fasting could really help people with diabetes but it would be very difficult for the NHS to start recommending it. Not sure I would necessarily recommend it to anyone unless I knew them very well. People's relationship with food is a very complex issue

Lemonthyme · 30/04/2026 10:35

zanahoria · 30/04/2026 09:18

I do understand why people are sceptical, eating disorders are prevalent in our society and horror stories about them are way more prevalent than success stories about responsible fasting.

I believe that fasting could really help people with diabetes but it would be very difficult for the NHS to start recommending it. Not sure I would necessarily recommend it to anyone unless I knew them very well. People's relationship with food is a very complex issue

True but instead they recommend appalling guidance with terrible records on efficacy. I was sent the "eatwell guide" and a guide on making sure I exercise a minimum of 150 minutes a week. When I'd already told my GP what I was doing which was in excess of the NHS guidance.

The risk if we don't start thinking about guidance which might actually tackle early signs of insulin resistance is that we then start using drugs to treat people instead when behaviour could be a cheaper (and possibly healthier) alternative. So I get your point but when the NHS is like this, it's difficult to see how they're going to have different outcomes? Basically everyone will be on WLI.

One 24 hour fast a week has helped where 5:2 did not
OP posts:
Lemonthyme · 30/04/2026 10:38

Ah you can't see it. It's the Simpson's episode with Flanders' parents who were "beatniks".

The quote is "We've tried nothing and we're all out of ideas".

OP posts:
zanahoria · 30/04/2026 15:59

Lemonthyme · 30/04/2026 10:35

True but instead they recommend appalling guidance with terrible records on efficacy. I was sent the "eatwell guide" and a guide on making sure I exercise a minimum of 150 minutes a week. When I'd already told my GP what I was doing which was in excess of the NHS guidance.

The risk if we don't start thinking about guidance which might actually tackle early signs of insulin resistance is that we then start using drugs to treat people instead when behaviour could be a cheaper (and possibly healthier) alternative. So I get your point but when the NHS is like this, it's difficult to see how they're going to have different outcomes? Basically everyone will be on WLI.

I went on an NHS education day but thought the NHS was a bit wishy washy considering the short window of opportunity to turn diabetes around. It seemed all on the level of 'why not got for a walk' or 'eat less rice'. Well meaning but not a lot of help.

The one size fits all approach does not really work and sends everyone in the direction of medication

I think they should offer special courses for people who are committed to turning it around via diet and exercise

Lemonthyme · 30/04/2026 16:14

They used to @zanahoria and despite my GP swearing he didn't refer me for my county weight loss service, I was referred by someone, about a week after I'd seen him to tell him I was trying really hard on weight loss and nothing was working. 🙄

But that service is currently both under review and over subscribed. A previous GP had told me that I'd have to be referred for that first before any drugs were prescribed (I wasn't looking for drugs but just advice.)

Anyhoo. The service as I understand it and as it was described by the other GP is just very much along the lines of a group setting but the same advice. Eat less, move more. It was them who gave me the eatwell guide and exercise guidance.

So I've taken it into my own hands. Looked at my blood results, tried to figure out what might work if I had a level of insulin resistance and it is.

You know it would be utterly bizarre if I turn out to be right that the once a week fast is reversing some of my building insulin resistance and that's why it's working. As I've said before, the actual fasting calorie deficit is no more than 1000 calories so that's not enough to lose 1-1.5 lbs a week which is what I'm managing.

Think about it, if they're not recommending fasting because of the risks of acquiring an ED then it means they're more prepared to prescribe a drug which is likely to need to be taken for life than to advise a free behaviour approach and just monitor patients.

I'm so glad I read that book. Genuinely. Because beforehand I had no idea that different fasting methods were different and would have different impacts on your body. I had taken it as "I tried 5/2 and it didn't work" and "16:8" feels too hard to do every day and too inflexible. I am such a convert.

OP posts:
zanahoria · 30/04/2026 17:53

Lemonthyme · 30/04/2026 16:14

They used to @zanahoria and despite my GP swearing he didn't refer me for my county weight loss service, I was referred by someone, about a week after I'd seen him to tell him I was trying really hard on weight loss and nothing was working. 🙄

But that service is currently both under review and over subscribed. A previous GP had told me that I'd have to be referred for that first before any drugs were prescribed (I wasn't looking for drugs but just advice.)

Anyhoo. The service as I understand it and as it was described by the other GP is just very much along the lines of a group setting but the same advice. Eat less, move more. It was them who gave me the eatwell guide and exercise guidance.

So I've taken it into my own hands. Looked at my blood results, tried to figure out what might work if I had a level of insulin resistance and it is.

You know it would be utterly bizarre if I turn out to be right that the once a week fast is reversing some of my building insulin resistance and that's why it's working. As I've said before, the actual fasting calorie deficit is no more than 1000 calories so that's not enough to lose 1-1.5 lbs a week which is what I'm managing.

Think about it, if they're not recommending fasting because of the risks of acquiring an ED then it means they're more prepared to prescribe a drug which is likely to need to be taken for life than to advise a free behaviour approach and just monitor patients.

I'm so glad I read that book. Genuinely. Because beforehand I had no idea that different fasting methods were different and would have different impacts on your body. I had taken it as "I tried 5/2 and it didn't work" and "16:8" feels too hard to do every day and too inflexible. I am such a convert.

I put diabetes into remission even before I got into fasting, although I believe it will be very useful in maintaining that situation and has helped me bring my cholesterol down to acceptable levels. The NHS advice was poor but I was lucky that I had a GP who believed that diet and lifestyle changes were absolutely essential to that process and that it was possible. There were also some very good books out at the time, particularly Roy Taylor's and I used to discuss these a lot with my doctor.

Lemonthyme · 30/04/2026 19:50

You're lucky. My GP looks barely older than my 15 year old and all of the GPs in my practice are clueless on perimenopause. To even get them to take me seriously on that I had to raise an official complaint. (Long and other story.)

So the fact you are sat there with perimenopause related weight gain despite a healthy diet and exercise regimen leaves everyone in my GP practice utterly clueless. I'm sure they don't actually believe me. It's one of the reasons I started tracking food using an app and I log my exercise on my watch. I can prove I'm doing everything I say I am.

I'm so bored of the NHS staff utterly ignoring any middle aged woman. It's only the long covid clinic nurse in the end who convinced them that I needed HRT to help my overall wellbeing but also my long covid symptoms. THEN they listened.

OP posts:
JumpLeadsForTwo · 01/05/2026 08:26

Lemonthyme · 30/04/2026 16:14

They used to @zanahoria and despite my GP swearing he didn't refer me for my county weight loss service, I was referred by someone, about a week after I'd seen him to tell him I was trying really hard on weight loss and nothing was working. 🙄

But that service is currently both under review and over subscribed. A previous GP had told me that I'd have to be referred for that first before any drugs were prescribed (I wasn't looking for drugs but just advice.)

Anyhoo. The service as I understand it and as it was described by the other GP is just very much along the lines of a group setting but the same advice. Eat less, move more. It was them who gave me the eatwell guide and exercise guidance.

So I've taken it into my own hands. Looked at my blood results, tried to figure out what might work if I had a level of insulin resistance and it is.

You know it would be utterly bizarre if I turn out to be right that the once a week fast is reversing some of my building insulin resistance and that's why it's working. As I've said before, the actual fasting calorie deficit is no more than 1000 calories so that's not enough to lose 1-1.5 lbs a week which is what I'm managing.

Think about it, if they're not recommending fasting because of the risks of acquiring an ED then it means they're more prepared to prescribe a drug which is likely to need to be taken for life than to advise a free behaviour approach and just monitor patients.

I'm so glad I read that book. Genuinely. Because beforehand I had no idea that different fasting methods were different and would have different impacts on your body. I had taken it as "I tried 5/2 and it didn't work" and "16:8" feels too hard to do every day and too inflexible. I am such a convert.

I also had that ‘I’ve tried 5/2, 16/8 with no effect before and therefore assumed that fasting wouldn’t work for me (along with not knowing whether to believe about the negative effects on cortisol for women fasting). I’d heard of longer fasts but thought I couldn’t possibly do that as my sleep would be affected and that’s already a problem with perimenopause. A friend had had success with OMAD in the evenings, but the thought of doing that for life was also depressing. It was your comment about you only actually missing breakfast and lunch to make up the 24hrs that made me try it, and I’m a convert now. We are all individuals though, and the NHS just doesn’t have capacity (or knowledge, or ability to deviate from out of date guidelines) to tailor individuals programmes unfortunately, so we are left to figure it out ourselves!

Lemonthyme · 01/05/2026 08:43

Agree @JumpLeadsForTwo but I really think the NHS should make the time and money for this. If any health service in the world is better placed than the NHS to invest in prevention than cure, I can't name it. After all, every £ spent on preventing illness is going to pay back in spades.

I've thought for a while that specific perimenopause support would be so worth it. In loads of GP services I know of, there is a contraceptive clinic which is nurse led yet there's not a menopause clinic. A lot of weight gain happens with women around this time and so that could be part of it. But just imagine if you had a really experienced nurse who had more experience than your average GP on menopause? Who could advise on everything from whether to try HRT to diet, exercise, mental health and signpost to other services where needed.

Anyway, a bit of an aside.

But yes, again I was a little worried about the cortisol thing but again, when you actually go back to the evidence, it's not actually there. It's just something that's been hypothesised then treated as fact.

It amazes me to be honest that there is so much research on calorie controlled diets and so much evidence that they fail long term and yet people still persist. Now there's the alternative with WLI people are jumping on those. Yet it just feels like some of the alternatives to either have been quite lightly researched or done so in a way which combines methods so much that it's hard to see anything concrete.

Anyway, it's working and still working so I'm happy with that!

OP posts:
JumpLeadsForTwo · 01/05/2026 08:51

Lemonthyme · 01/05/2026 08:43

Agree @JumpLeadsForTwo but I really think the NHS should make the time and money for this. If any health service in the world is better placed than the NHS to invest in prevention than cure, I can't name it. After all, every £ spent on preventing illness is going to pay back in spades.

I've thought for a while that specific perimenopause support would be so worth it. In loads of GP services I know of, there is a contraceptive clinic which is nurse led yet there's not a menopause clinic. A lot of weight gain happens with women around this time and so that could be part of it. But just imagine if you had a really experienced nurse who had more experience than your average GP on menopause? Who could advise on everything from whether to try HRT to diet, exercise, mental health and signpost to other services where needed.

Anyway, a bit of an aside.

But yes, again I was a little worried about the cortisol thing but again, when you actually go back to the evidence, it's not actually there. It's just something that's been hypothesised then treated as fact.

It amazes me to be honest that there is so much research on calorie controlled diets and so much evidence that they fail long term and yet people still persist. Now there's the alternative with WLI people are jumping on those. Yet it just feels like some of the alternatives to either have been quite lightly researched or done so in a way which combines methods so much that it's hard to see anything concrete.

Anyway, it's working and still working so I'm happy with that!

That would be amazing. The NHS was never set up to prevent, only treat illness but 75+yrs on, there needs to be much more of a move to prevention with the evidence pointing to increasing rates of cancer (especially in younger people)/ dementia/ inflammatory conditions with a clear
link to lifestyle issues.

zanahoria · 15/05/2026 09:28

I am 38 hours into a fast so just had the second night's sleep and one of the best I have ever had while fasting. I really want to take this to 72 hours but 48 hours would be good too. It is becoming easier as my body gets used to it. The first few long fasts I had I felt completely bewildered as the experience was so new, right now I am feeling good. Plus, I had not fasted for two weeks but focused on a good diet and am sure that helps when you go again.

I am prepared for my mood to change at any moment, I have learned that can happen but right now I feel calm, contented and not hungry and confident I can last until this evening.

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