From Chris Kresser’s weekly email. Apologies in advance for including the whole thing, though minus the sales pitch.
I recently came across a great new paper in the New England Journal of Medicine called “Effects of Intermittent Fasting on Health, Aging, and Disease.”
It summarizes the accumulating evidence suggesting that skipping meals (and snacks)—aka “intermittent fasting” (IF)—can have profound impacts on our health.
Researchers originally thought that the benefits of IF were mostly due to weight loss.
However, this is no longer the case. Evidence now indicates that intermittent fasting has several positive effects that are unrelated to weight, including:
Improving blood sugar regulation, heart rate, and blood pressure
Increasing stress resistance
Slowing the effects of aging
Reducing inflammation
Improving cognitive function
Why does IF have so many benefits?
Being in a fasted state activates cellular pathways that remove or repair damaged molecules and improve our defense against oxidative and metabolic stress.
There are several different approaches to IF, including alternate-day fasting (eating only every other day), 5:2 fasting (eating five days per week, and fasting two days), and time-restricted eating (typically eating only during a six- to eight-hour window each day).
All can be effective, but in my work with patients, I’ve found that time-restricted eating is the most practical and sustainable approach for most people.
This might mean eating only between noon and 8:00 p.m. each day (for an eight-hour window) or between 8:00 a.m. and 2:00 p.m. (for a six-hour window).
There’s some evidence that eating only in the morning or daytime is better than a later window, i.e., 2:00 p.m. to 8:00 p.m. However, this is challenging socially for people who want to eat dinner with family and friends, so most find it easier to include dinner in their eating window.
If you’d like to give time-restricted eating a shot, make sure to start slowly to give your metabolic machinery a chance to adapt.
For example, you could begin with a 10-hour food window five days per week for the first month, then go to an eight-hour window five days per week for the next month, then an eight-hour window seven days per week, then, finally, a six-hour window seven days per week.
Also, remember that there’s no one-size-fits-all approach when it comes to this stuff.
I’ve found that some of my patients don’t do well with prolonged time-restricted eating, especially with shorter (i.e., six-hour) windows every day.
I’m not sure why this is the case, but I suspect it’s because fasting, although beneficial, is a stressor. If someone already has a very high level of background stress, the additional stress of time-restricted eating may push them over the edge.
Another potential cause of difficulty might be for people who are already underweight or in a hypocaloric state due to chronic illness. In these cases, time-restricted eating may accelerate weight loss and further decrease calorie intake, which isn’t desirable.
As always, let your own experience and your body—rather than a theory—be your guide.
Written by
BadHare
To view profiles and participate in discussions please or .
I tried this regime after reading Michael Mosley and Rangan Chattergees excellent books.
I gave myself a window consisting of ,if I ate breakfast at 8am then I didn’t eat again after 8pm.I ate sensible home made food,no dairy and no gluten where practically possible,I didn’t gorge myself in that time frame and I actually did pretty good,I did a lot of meditation too as I had a lot of destressing and healing to do and I lost over two stones over that 6 months.
Sadly I lost focus for variety of reasons and didn’t continue with it and piled a good bit of weight back on again. I’ve no excuses it was all down to my choices.
What I will say is my problem was because I’d beaten HPylori and was starting to feel well again with my gut I started eating the wrong things all over again and now I’ve had the wake up call I’m going to start all over again and this time my eating habits will be my new lifestyle habits,I won’t be so complacent again.
I’d say give it a try you’ve nothing to lose and you will certainly benefit from it but read up as much info as you can,the two guys books I mentioned are a great start for you. Good luck
I know I'm in ketosis too, but weight is between 12st 10 and 13 st 2lbs daily. My 'window' for eating is between 12 midday and 6 pm daily - what would happen if I just fasted and went anorexic, would I still stay the same? It makes me want to just give up.
Doing low carb too 20g max daily, but only having mushrooms apart from meat/fish/eggs, what a way to live.
All the things I love and can't eat! I am getting to the stage where I think blow it, what's the point if I am not losing anyway????? The B, thyroid is the bain (? Spelling ??) of my life!
Have you joined the high fat low carb forum. Some interesting information available that may help you broaden your diet so you might enjoy more variety. I have moderate rather than low carb as I need some grains for amino acids as I’m veggie.
Yes I am a member BadHare, I can get into ketosis pretty quickly - I use ketostix to check that, but I just don't lose any weight. I know people will think that I can't be doing it correctly, but I honestly am not eating anything that I shouldn't be eating. I have cut even my salads down to the bone, but no weight moves appreciably. Just a constant up one, down one day in day out, 12st 13lbs today 12st 11 lbs yesterday.
I am preparing lunch now, sea bass with mushrooms, but can't have it until midday.
I don't have any problems with the meals at all, but I am doing what I am supposed to do, which makes me very angry, because if I had cheated I could not complain, though why would I cheat if I want to lose weight? It is doing everything by the book and not losing which drives me silly.
That’s frustrating for you. Are you getting enough micronutrients such as vitamin C, folate & B12? Are you thyroid hormones optimal? I know when I was trying hardest to improve my health, I was doing the opposite by eating tofu & soy milk every day. Expensive mistake re what I was eating & scuppering my hormones further! I’m still veggie aside from NDT, & no other goitrogens seem to affect me, though I’ve lowered my hormones since I started injecting B12 weekly.
No, everything is upside down with me, that's why I am battling to get my thyroid results from my GP. I had a blood test done here on Tuesday, should have the results today. Only TSH though and the one to check that I am/am not type 2 diabetic.
That’s annoying, & your GP likely wouldn’t know what the results meant anyway. I went in with a new spinal issue last month, & they tested my T3, iron, folate, & B12. 🤭 I bet they’d’ve refused all of those had I asked. Bit of a waste of money as I take T3, eat & supplement iron & folate, & inject B12. At least I’ll know my levels though I’d have asked them swap those four for ferritin had I noticed the list before the blood draw.
Do you trust yourself & symptoms enough to try NDT? I’m ok in summer months on T3 though I burn more easily, but can’t cope without piggy meds from autumn to spring.
YES!!! fuchsia-pink I wouldn't wish it on my worst enemy, but I am the same, no loss of weight!!!
I stick to my diet, walking for an hour a day most days, weather permitting. Tried veggie, tried low carb high fat, tried calorie counting, nothing works.
It is soul destroying isn't it? And my size 10 doc sat behind her desk as she told me that in order to lose weight I just had to burn more calories than I take each day! Rubbish.
I stick with it because (a) I'm used to it; (b) I'm hoping for all the other benefits that are meant to accrue and (c) my weight is stable - and I'm slightly scared it would increase if I started eating breakfast! I certainly don't eat any more in the "eating window" than I did before.
For what its worth, I did lose some weight last summer - I can only do it when it's hot - by eating normally (for me) on Sundays and for six days having one small meal a day [protein and veg/salad] plus two mugs of tea - and just having hot or cold water the rest of the time, with one green tea a day when the unrelenting hot water got too dreary - and have kept it off. Kept it up for 5 weeks, lost 5 kg; stopped when blood pressure got too low.
A friend (with no thyroid issues) has done similar but ate just cherry tomatoes and satsumas for lunch and snacks - and lost 2 stone easily.
I have managed to lose 3 stones before 2011/2012, got down to size 12, kept it off until beginning of 2013 and went to buy new clothes after the New Year, then it slowly crept on again, relentlessy no matter what I ate or didn't eat, nothing stopped it until I was 14 stones again hovered up and down for a while at that level.
This time last year I had istarted to lose again - no idea what was different, same diet, Got down to 12 st 5 lbs and probably June ish, started to gain again here I am now usually betweeb 12 st 11lbs - 13st 1lb, up a pound down a pound. But this morning I am 13.3, so gained more than a pound today.
I think I am too sick to take this for much longer, I want to throw the towel in and submit, but that won't get me anywhere.
The whole family think I am crackers, no one believes me that I am sticking to my diet. Why I won't eat after 6 o'clock at night or before midday, mainly 1 meal and an early evening snack. No dairy, and reduced my veggies because I wasn't losing, dip sticks bright purple, usually late afternoon is highest ketones, but gaining!
I forgot to say that when something changes and I can lose weight, I lose it easily, and pretty much steadily. I have to keep to a diet, but I don't mind a diet, no pain no gain. I kept to max 800 calories a day, every day, no 5:2 for me. Now the only thing I haven't tried is a fast, don't know whether I have the courage for that. Everyone is badgering me now because I won't eat breakfast, the would have me sectioned if I stopped eating I think.
It'll be interesting to see your blood results when you finally get them. If you look at my previous posts, you'll see that I put on weight 1kg a week (on normal intermittent fasting) for 2 weeks when I was taken off T3 - and took it off again with no effort when my lio was restored. And they say it's all in the mind?? Rubbish - it's all in the meds!
Nothing to tell really fuchsia-pink. He only tested TSH and that was 0.3 I think, the printout is downstairs, so not certain of that.
But they gave no T4 or T3 values.
My type 2 was negative.
He looked at my old results and told me that T3 was unimportant because my body took what it needed from T4 supplied via TSH. I did ask him about people not being able to convert adequately, he said that was rubbish and I knew I could not expect any help from him.
Told me how elderly I am and that I didn't need so many calories because I am elderly, told me that I need to do 'Fitt' exercise where you exercise moderately but add in a few bursts of high activity - enough to raise my heart rate - along with the moderate activity!
Told me that when he does a few 'burpees'(spelling?) he is cream crackered for the rest of the day because THAT is proper exercise 'don'-cha-no'! Burpees are being on the ground, in a full length pressup, on your toes with arms fully extended and then push up to a standing position and repeat.
I told him I was not going down that route and he could forget the exercise bike too! I already have back problems, not trying that.
He was not at all convinced about my efforts of walking briskly for an hour a day every other day minimum if the weather was dry. That was better than nothing, a bit 'tame', I really needed to push myself so that the weight drops off me because..................................... yes, I am just a greedy piggy really and I am eating far more calories than the calories that I am burning off! Simples!!!!!
However another blood test on Tuesday for fasting blood sugar, thyroid antibodies, gluten in tolerance and to check my Phosphates which he said were high at 222 or so.
I asked what they were about and he said 'alcohol use'! How many times a week did I drank alcohol? I tried to remember the last alcohol I had, couldn't remember the day, (but I had had 1 shot of dark rum and I had had it in the local bar last Sunday night) - blood test was on Tuesday. We went in there at 6pm and were at home by 7.30 pm I always drink diet pepsi when I go into a pub, (but never at home) my brother in law asked me if I would like another drink, I had some pepsi left in my glass and I had a shot of rum put into my pepsi.
So then he showed me that these phosphates had been raised on one of my old results, I think it was in 2005, he showed me that they had been over 400 then and said there you are, you are reducing them nicely, well done! From15 years ago????
I think he thought that I was about to go into sclerosis any minute. So he thinks I am a lazy, greedy drunk it seems.
When I told my brother in law when he got back home, he thought I was jesting! Because I had to ask him what night had I gone to the bar with him and had a shot of dark rum?
So I really can't see that I will be making any headway with this GP, at least my thyroid results from home showed TSH, T4 &T3 which I hadn't expected, but he doesn't believe in testing for 3 and 4!!!
Oh yes, I forgot that the GP told me that I must have snacks ready for when I get hungry! He showed me a plastic container full of nuts and things, "not like the girls in the office, who have lots of cake around, and don't eat fruit either because there is a lot of fructose in fruit you know, snack on nuts all day!"
I came away quite honestly thinking that I knew a lot more than he did about calories, glucose, fruit, insulin raising snacks of any kind. I know he can't help me.
I have just totted up my food intake for the day, 840 calories and 21g of carbs, about normal. Black coffee is my big vice, I would have it with cream, but I have been trying to do without dairy. I don't know how much longer for though, I miss butter and cheese.
I will start another thread later telling of my visit to the gp today, but it was a dead loss really, though I am not type 2, which is what I thought anyway.
Ditto with me. Time-restricted eating suits me, and I'm very low carb most of the time. I still seem to be gaining weight though. My sleep is terrible (apnoea + another undiagnosed problem + demanding old cat), which affects mitochondrial function, so this may be a major factor in my own case.
Hi Hollwoman, I have terrible sleep too for years, night terrors. The Endo is checking my pitruitary. Ive been so much better since taking NDT, DHAE in an adrenal support and all the vits recommended on here. Dont know which has done the trick. Think DMAE x
Me too Hillwoman, I hate the thought of going to bed in case I am going to be lying there all night again. Funnily enough, I have a cat too, who sleeps in the bedroom with me here, and usually he fancies galloping around the house like a mad thing and calling to me while he's thundering around
I think Kresser makes a good point that it may not suit everyone and I'm currently assessing that for myself. As a family (including the dog - key member!), we IF on Mondays but I generally feel less well those days which may be down to that or the fact I do enema that day.
I suspect it's the former partly because of past experience with fasting. A couple of years ago, I did a long juice fast and it made me feel worse. My thyroid levels also dropped (eg TSH 0.05 or so) but had recovered by next readings and ok since.
Hi userotc.I felt no I’ll effects whatsoever when I did the 12 hour windows fast it really helped my gut issues and ibs. I think in your case you are probably detoxing and that would make you feel yuk but maybe try again and over time when toxins are easing off.you could also put a punch of pink salt 🧂 n your water which is really good for the adrenals and will help replace your body salts while your Detoxing.good luck In your choices I’m already feeling the gut benefits again so I’m sticking with this now.x
I have found the time-restricted IF of an 8-hour window much easier than calorie-restricted on two days (i.e. 600 calories per day). The latter puts a huge stress on the body and while it was the most effective diet I've ever been on in terms of losing weight, I doubt it's beneficial to those with adrenal problems. I'm also concerned that it might lower FT3 levels (as other calorie-restricted diets).
The 8-hour window in effect does lower calorie intake, but it's not so severe and it still gives the body to recalibrate and recover. I need to return to this regime - easy to get out of the habit and difficult to resume.
I like eating to much to do 5:2, though an occasional 24 hour fast is ok when I loose my appetite in hot weather. I know little about adrenal conditions. Sometimes we have to try something alternative to see if it suits us. I started restrictive eating prior to taking thyroid meds but haven’t noticed a difference in efficacy when I eat breakfast, just being hungrier.
Hi I never did the fasting or calorie restricting I just did the 8am to 8pm window and made sure I cooked everything from scratch and avoided gluten and lactose/dairy as much as possible.I made sure I didn’t snack between either and I did really have good results but as I said I got complacent because I also had beaten the HPylori bacteria which caused me so much pain and as I got better and fitter, I thought I could just go back to my old eating habits and before I knew it I was piling the pounds on again and my pain bloating and nausea all returned slow but sure so I’m back on track again and all I can say is I’ll do my utmost not to make the same mistakes again but I’m not being obsessive about it p,just trying to stick to the practical side.good luck everyone x
Content on HealthUnlocked does not replace the relationship between you and doctors or other healthcare professionals nor the advice you receive from them.
Never delay seeking advice or dialling emergency services because of something that you have read on HealthUnlocked.
Weight loss on intermittent fasting even better than my last post 3 years ago! 
Time Restricted Fasting?
Weight loss and hypothyroid: intermittent fasting?
Intermittent fasting affecting thyroid values
Underactive thyroid and Intermittent Fasting (16:8)
