To think the 5:2 diet is just dangerous nonsense?

[MrsMattBomer]

A girl I teach in sixth form was telling me about it today. I was a bit baffled by it, brought it up to a colleague who said it was amazing and really works.

Am I right in thinking it's basically just eating what you want and then starving yourself for two days? Is this not incredibly dangerous? Surely it's an eating disorder of some kind, not a diet!

TIP, it can take 6+ hours to properly assess the quality of a single RCT. So I'm not gonna find the gold-standard quick for you (I charge £17/hr :) ). I assume you want weight loss trials, not whether ginger makes your hair grow thicker or fish oils stop heart attacks, etc.

At a glance, these trials look kind of good. 12 months, > 100 pts randomised, good journals so hopefully got good peer reviewers. Could drop numbers to 50 in each arm & only 6 months in an evidence search, but why drop standards when plenty of studies were done to higher standard, and the desired outcomes happen over long periods (1 year+).

52 week trial, 115 obese indivs, on 2 low calorie diets with prescribed aerobic exercise. One diet was low carb & one was high carb: the pts did about equally well on many health indicators, on both diets.

52 week trial, 439 postmenopausal overweight women, on diet or exercise or diet+exercise regimes. Had most health benefits for both of the weight loss arms, better than the exercise only arm which was better than controls.

I can't access full text from home so no idea what the adverse events profiles were, though.

wrt 5:2, I'm a huge fan of do what works for you. I don't think I slagged anything off, I just said don't claim evidence is great if it's not. I'd try 5:2 if I thought I needed something like that & would stick it.

*hmmm.. should have said "calorie reduction" when I wrote "diet" or "weight loss" on 2nd trial. Oh well!

I swear by it. As I approached 40, my weight crept up and up and I really couldn't see any where of reversing the decline into a fat, frumpy middle age - I store all my fat around my middle, so any weight gain was really noticeable. When I was 43 (BMI 26) I watched the three part Horizon documentary which looked at what diet suited particular people. The study group was divided into three groups - feasted, emotional eaters and constant cravers. As on as they described the features of the constant cravers, I knew that was me.

The diet they recommended was the 5:2. I was a bit sceptical to start with, but I lost 17lbs in 6 months (down to a BMI of 23) and two years later, have kept nearly all of it off. It doesn't feel like a fad - it's just a way of life now, and I think I'll be following this way of eating for the rest of my life.

So YABU.

medschool
ah bless, £17 an hour. I do not set my alarm for that - nor does BigChoc
please do not condescend those of us who analyse data for a living (medical or otherwise)

I've not clicked on your links as they are not transparent
(habit as an auditor)

5:2 works
NHS advice does not
5:2 as a variant of IF / ADF has a 70 year data set
the NHs plate of food has zilch

I can't imagine the ethics approval would be particularly difficult.

There have been diet based RCT trials before and recently they managed to admit patients for a trial so they could carefully control the diet they were putting patients on.

The ethics is a bit more complex for this as the focus is on fasting as opposed to calories restriction. There was discussion about PP selection rather than it being self selection, via volunteers. The criteria mooted included diabetes II, various CV conditions, cognitive function, metabolic syndrome, and a whole host of other, diverse issues.

So yes. Once they decided the scope getting it past ethics would have been a tad more difficult than your usual RCT study.

I just wish I could find the bloody thing. It may not have gone ahead! If I could remember the UK university that would be a start!!

I did the diet and I had a lot of hair loss.

Would you follow

1. an eating plan devised by a doctor with scientific research
2. an eating plan devised by a celebrity

Neither, ivykat

I worked with local NHS dieticians for a couple of years. I ran exercise and meal planning classes for patients trying to lose weight prior to bariatric surgery. The dieticians were a bit of a mixed bag, mainly because they have to stick rigidly to the NHS guidelines. But the GPs who were supposed to support the group were hopeless, dangerous even!

I'd go to a non NHS dietician and have a long discussion about possibilities.

That is how I chose a mix of IF and GL. It works really well for us and has the added benefit of being partially acceptable to the NHS, as it closely resembles the Mediterranean way of eating - quickly becoming the NHS favourite and may soon replace the current advice!

Thanks Talkin

I agreee Fitbit may be very inaccurate, my body fat has been the same for about 18months, which is suspicious as my weight has fluctuated by 5 pounds...

My TDEE is 1542, so my FitBit saying 2800 cals average could be 40% over estimate?

TBH I don't count calories, just run a lot, walk a lot, eat a lot of healthy stuff and don't snack.

I'd be worried I'd lose weight on 5:2, and end up underweight. I'm mid 40s 9st 2 at 5'9; if I go below 9st I look a bit scrawny.

I am interested in gaining the benefits regarding dementia, diabetes and so on.

GreatPoint - out of interest, I just put your stats into the tdee calculator (using age 45 and moderate exercise options) and it says your tdee is 1999. Why do you think it is 450 calories lower?

My tdee really is in the 1500s but I am 10 years older, 5'2" and very sedentary. What you have put in your post just looks wrong .

Bibbity, I entered 'sedentary' on the calculator as per TiP's instruction? I am very active though.

I'd agree with you Blanche, probably because the NHS are dictated to and to many guidelines set down through politics so would also op for a non NHS dietician

After years of 'dieting' I tried 5:2 this year and have lost all my baby weight and more. I am fasting today and have eaten a carrot, 2 x celery and a whole pepper with some hummus for dinner I am going to eat a homemade soup made from butternut squash, onion and sweet potato. Is that dangerous? Really? I do that twice a week and I am still eating 5 portions of fruit and veg. On my non fast days I still eat a healthy balanced diet BUT I can have a chocolate bar or a glass (ok bottle) of red wine if I fancy it. Since doing 5:2 I have never had a cold, my psoriasis has cleared up (it helps with inflammatory diseases) and I am a healthy BMI. This is the best diet I have ever done simply because it does teach you balance it's alright saying it's dangerous to starve yourself two days a week (which your not) but what about those who are stuffing their faces with crap 7 days a week, over eating and getting diabetes, heart disease etc which 5:2 has been proven as a method to reverse?

Sorry, I didn't see where Talkin had instructed you to do that (seems a bit odd if you are not a sedentary person).

But then some of the long term 5:2-ers bend the rules rather a lot! First of all they allow themselves the absolute minimum possible calories on non-fast days and secondly they do an awful lot of exercise. Then the fasts started becoming 14, 16, 18, 24 hour fasts and beyond. Then the fast days started reducing from 500 calories to 400 calories to 300 calories, etc.

It was all getting a bit too much like endorsement of disordered eating on those threads for a while there. Disclaimer: I'm sure most people are very sensible and the atmosphere is a lot healthier on the threads now!

bibbity that's what I was doing. I was struggling with willpower on the 500 days, then cutting right back on the others too! I was eating hardly anything didn't last long though.

"ah bless, £17 an hour. II do not set my alarm for that - nor does BigChoc"

Gosh, TIP, did you mean to be so rude. Why ask a Q if you didn't want an answer or did you really just want an argument, or to pretend you won the argument that never existed. I will avoid you in future.

It didn't make her sound rude imo, just a bit of an arse!

So you're basing this opinion on what a sixth-former told you? (Disclaimer: I'm sure she's a lovely girl etc)

It wasn't for me but it is for plenty of people. Maybe you could actually read around the subject a bit. There's some pretty weighty evidence in favour of short fasts and, no, if you're doing it right, you're not supposed to binge on other days. If you are, then your eating is disordered. That's a whole other ball of wax.

So how long is a fast, then?. Ten hours? Twelve hours? Six hours? Twenty four hours?

I don't eat after 7 and before 12 on a regular basis. That a fast?

There's an article in glamour magazine (not great I know) that says research shows it has negative effects in women, including infertility. They say the positive research is done on mostly men and women react differently. No idea the credibility of this research, I have no interest either way, but just thought I'd mention this incase anyone having fertility difficulties or planning a family wants to check out the research behind it just to be on the safe side.

Re the actual diet, I have allways wondered if eating the recommended 3 meals a day/2000 calories makes any sense. When I was a skinny student I ate a huge mixed of food including junk stuff but was also simply to busy to eat sometimes or too tired or to skint. If I concentrated on eating what was supposedly healthy I would have weighed more and been forcing myself to eat when my body didn't want to. That doesn't make much sense to me.

that is true Indrid. The three meals a day thing is just too much most days.
I would normally have one meal and two snacks...

absolutely
in the IF / ADF medical research, a fast is generally deemed to be 16 hours or more .... so early supper through to lunch .... with no/minimal calories

why use sedentary TDEE
the reason for working out that number is very simple
most people massively over estimate how active they are so a mental picture of their sedentary needs is useful

Is the 5:2 compatible with breastfeeding? Would fasting affect milk supply?