Beowulf Effect

The Horror Has Returned; And a Literary Analysis is Attempted

Honestly this entire post is really really boring even to me! I haven’t been this bored since I tried to write up my PhD. Just skip to the last section unless you’re more of a fan of my witterings than I myself am.

The only reason it’s a blog post at all is because writing blog posts helps me think and keeps me honest, but that doesn’t mean you have to read it! Just having-had-the-intention-to-publish will do, and I’ve already done that. Now I have to follow through or my brain will learn that I am cheating it.

But if anyone does have the heroic patience and attention to detail to plough through it and check various past posts to find out how I’m fooling myself this time I’d really really appreciate corrections.

Awesome work by ChatGPT (GPT-5.5, OpenAI)

So, I started all this PUFA avoidance about three and a half years ago in an attempt to control my new and rapidly worsening obesity problem, and I know that that’s what most of the people who read this blog are interested in.

But that’s not actually what I’m interested in! Or at least, not the most important thing.

At first PUFA avoidance was just a half-hearted sort of thing, because I was thinking ‘There’s no way I can work out if this is true or not, I’ll just have to try it’ and for the first six months it didn’t seem to be making the slightest bit of difference to my rising weight so I wasn’t taking it very seriously.

Although even then, even before I’d finally noticed how much PUFA was in peanut butter and stopped eating it, I did notice and write:

In terms of general well-being, it’s a massive win, in fact my general state of health improved to the point where the deleterious effects of sulphites became obvious, which has lead to me feeling even better. No more mysterious tiredness in the afternoon, no more afternoon naps.

---

The thing that really grabbed my attention was the fact that the first time I tried the ex150ish diet it completely fixed my tiredness, and I wrote:

But suddenly I’m not so interested in weight loss per se

I’m completely derailed and nerd-sniped by the feeling of ketosis itself.

I’ve got suddenly limitless energy.

This is almost how I used to feel, back when I would have described myself as well.

The feeling that I might suddenly get tired, or that before doing something I should make sure that I’m properly rested and prepared, that I’ve had on and off since I was about forty, is quite gone.

I feel like the famous Duracell Bunny. Nothing slows me down or tires me.

For ten years I’ve been a Spoonie. Now I have as many spoons as I like.

Conversation, walking, playing chess, cycling, none of this is remotely tiring any more. Once you do one thing, on to the next.

I remember that I’m extremely extroverted. When I finish talking to people I feel energized, and my first thought is that now I need more people to talk to.

Friends agree. I’m back to my old self, before it all went wrong.

For the record, apart from the extroversion, I think this is how men are supposed to feel.

I’m pretty sure that’s how I felt for the first forty or so years of my life, with a brief exception when I lived in London while trying to do a PhD, where I got mysteriously tired and depressed and put on weight. ¹

I also wrote at the time:

But it feels thin, somehow.

I don’t feel like I’ve got extra power in reserve. I could handle a long slow rowing outing in this state, I think, but I wouldn’t want to do a regatta.

I remember this feeling!

This “ketosis” is the post Boston Marathon, post cycle to Oxford feeling.

When you’ve burnt all your carbs and are running on the emergency back-up fat burning system. (doh!)

And I noticed the “two fuels” problem that same week, where I could get mentally tired while still having endless physical energy.

And I pretty quickly guessed that my long curse of tiredness is actually ‘broken glucose metabolism’, which I strongly suspect is something to do with PUFAs.

---

For me, this is way way more important than what I happen to weigh on scales. At 100kg/BMI 32 I am a bloated and unnatural horror, but not so bloated that I frighten children, and at fifty five years old I am long past the point where I worry about whether I’m attractive or not. But I didn’t even notice I was getting heavier until the pandemic in 2020, when for unrelated reasons I weighed myself for the first time in years and was surprised to find I was 93kg/BMI 29 instead of the 85kg/BMI 27 which had been ‘my weight’ for my whole adult life.²

So I consider getting rid of this long curse of fatigue to be the primary outcome of all my experiments, and the weight aspect is a nice-to-have but not the important thing.

And so I’m in the bizarre position of trying to do experiments to measure the change in something that’s basically impossible to measure objectively.

---

For a long time I’ve contented myself with measuring the daily dose of thyroid drugs that it takes to keep me basically functional and not showing the symptoms of either hypometabolism or hypermetabolism. That’s a pretty objective measurement because if I’m hypo I tend to get plantar fasciitis almost immediately, followed by a whole host of other nasty symptoms if I don’t fix it quickly. And if I’m hyper I’m overheating, anxious, a bit manic, and have trouble sleeping.

And that thyroid dose has gone pretty monotonically down over the last few years, which I’d assumed was evidence that the actual underlying problem was getting fixed.

But that’s kind of useless now, because the amount of thyroid that I seem to need has gone so low that it’s practically homeopathic, and indeed at the moment I can’t tolerate any of it at all.

And to my surprise I’m still really tired, in fact it’s worse than I can ever remember it being since I had, and should probably have been diagnosed with, actual mysterious Chronic Fatigue Syndrome, which was a life-ruining wasting horror, even though at its worst it was only quite a mild case. Pity the real sufferers out there, there are a lot!

My made-up-against-medical-advice thyroid cure almost completely fixed all that. I used to say that “my only medical problems these days are sports injuries”, and that was true, but I was never really ‘back to normal’. I was never an endurance athlete after that, stopped rowing, stopped cycling³, stopped skiing, even stopped travelling, and sports I’d once thought of as ‘barely even exercise’, like village cricket and crap tennis, took some dedication to keep playing, and an old friend from rowing days (who’s the same age as me) once rather memorably described me as a ‘limited man who’s learned how to live within those limits’, which struck me at the time as an extremely insightful and inarguably true description.

But now it’s back, and it’s bad. I’m pretty regularly feeling the need for an afternoon nap, and sometimes I actually sleep, and wake up feeling refreshed, and sometimes I just lie down for a bit and then feel fine, and sometimes I sleep and then wake up still feeling tired.

At that point I’m not ‘limited’. I’m ‘mildly disabled’. If I have plans for the evening like singing or playing chess or meeting friends then I tend to take a preparatory nap just in case.

But there are at least no other hypometabolism symptoms. If there were I’d just raise my thyroid dose to fix them. But at the moment if I try that I just get hyper and overheated, and still tired.

So as far as I can tell, all the other symptoms of CFS are completely gone, and yet the principal symptom of tiredness is back. Not as bad as it once was, but still disabling, not just a minor annoyance any more.

---

What Do I Know About My Fatigue Since 2023?

Well I have my notes and my various blog posts! And I have a definite impression that ketosis always improves things.

For the first year or so (Summer 2023-Summer 2024) I don’t remember paying much attention to fatigue, which implies that it was just burbling along annoyingly in the background, but not much of a problem.

And in the autumn of 2024 through to the summer of 2025 I had an actual full time nine-to-five consultancy contract.

And I remember that for the first half of that, to my surprise, I didn’t have much in the way of fatigue at all, even though it involved an hour of cycling to and fro every day, but that at Christmas 2024 I went home to visit Mum and came back with a real fatigue problem.

It was getting so that I routinely felt shattered and listless and not very productive at all around three o’clock, and started leaving work early to go home and sleep. That seemed the honest thing to do as a contractor paid by the hour, and quite often I’d go home, sleep, feel better, and then go back and work the evening.

After a month or so of this, I felt that I had to tell my boss, who is also a personal friend, that I was not firing on all cylinders, and he was very very understanding. He just said: ‘Do what you can, go home when you need to, you’re good enough that I want you working on this even part-time if you can’.

And weirdly quite quickly after that I just got better again, and for the rest of the spring and early summer of 2025 I was pretty much fine.

By May 2025 I was happy that I’d come to some sort equilibrium weight at 97kg, and I started messing about with variants of ex150 that involved eating carbohydrate (fruit, chips, ice lollies, ice cream). Some of those choices were made because we were having a very hot summer and I was persistently overheating, noticeably more so that other people around me.

It doesn’t actually look like I tried dropping my thyroid dose at this point, I guess I was just assuming that the problem was the heat, until June when it became obvious:

June 2025

It’s been very hot here (around 30C) and I’ve been consistently overheated for the last week, sometimes super-energetic, sometimes very tired, sweating and walking around with no shirt on even though other people seem to be managing ok and some weirdos seem to have managed to feel cold at times. That is pretty clear hypermetabolism/thyrotoxicity, I’ve got no hypo symptoms, and I’ve been dropping doses of thyroid to try and deal with it and that seems to have worked.

I left that gig in July 2025, project done and it was Summer so I didn’t feel like doing any more, but it wasn’t fatigue or even boredom, I was still enjoying it, it was just ‘it’s sunny out’.

It sounds like for a while afterwards I managed to be mainly hypermetabolic, with associated tiredness. It is very irritating that tiredness and fatigue are symptoms of both hypo- and hyper-metabolism, but all the other symptoms are pretty distinct, so it’s usually not that difficult to tell which state you are in as long as it’s not just tiredness.

July 2025

My thyroid dose has dropped a fair bit, I’ve been getting less overheated and I’m feeling fine.

And then when I tried adding bread to ex150ish, I became suddenly hypometabolic, also with associated tiredness

July 2025

neither of those things would have bothered me too much but after a couple of days I also suddenly started getting tired. Three times in the last four days I’ve started feeling really sluggish and brain fogged, gone to bed mid afternoon and slept for a couple of hours. And one day I got a really characteristic ache in my legs which has always been an early-warning chronic fatigue symptom. And I got a surprisingly low waking temperature reading one morning for no reason.

And then hyper again:

July 2025

And it has made no bloody difference at all, I have continued to feel really tired, lots of afternoon naps, overheating horribly and sweating all the time, headaches, weight rising rapidly, and blood pressure now through the roof and frankly scary high.

I’m occasionally feeling tired, but not usually to the point of sleeping in the afternoon, and some days I’ve felt lively.

July 2025

I’m still feeling a bit too hot generally and dropping my thyroid dose to compensate, it’s almost nothing now, so I wonder if all that was just thyroid overdose.

And when I went to visit Mum in August 2025 I was frankly hyper:

August 2025

But it didn’t, I felt far too hot, I couldn’t sleep, my mind was racing, and I was simultaneously exhausted from lack of sleep and full of restless energy.

And then after that, having reduced my thyroid dose down to nothing, hypo again:

October 2025

So there was a period after I came back from home where I wasn’t taking any thyroid and was fine. But in the two weeks since then I’ve felt increasingly sluggish and tired, and eventually last week I started getting plantar fasciitis again, a very characteristic pain in both feet which has always been a hypometabolism symptom for me.

And then after that everything just got a lot better and I started to feel fine again:

And then last Christmas (2025) I maledicted myself by writing:

‘The almost complete remission of my once-crippling chronic fatigue is the best of them’

And as I remember I wrote that because my fatigue, although still present, was not much of a problem, and my necessary thyroid dose was down to very low levels, without any hypometabolism symptoms at all.

Christmas 2025, I managed to poison myself by eating for several days a curry that Mum had unwittingly made with sulphites, and that made me feel terrible, very characteristic nasty headaches and shattering tiredness, but once I’d got through the curry and found the source of sulphites I recovered rapidly and completely, while eating a lot and putting on loads of weight.

But then I came back to Cambridge:

The only fly in my ointment is that I’ve been feeling absolutely awful. I’ve had a couple of mild sniffles in the last couple of weeks, and maybe they were something to do with it. I can’t believe that a couple of weeks ago I wrote ‘the near-complete remission of my chronic fatigue syndrome’. It’s totally back now.

It’s not nearly as bad as it was before I started taking thyroid, and I’ve got none of the many other symptoms apart from the tiredness, but most days for the last couple of weeks I’ve been waking up feeling a bit sluggish, and then by five o’clock I’m so tired I go to bed for a couple of hours, and usually wake up fine and end up going to bed late and the cycle repeats. I feel more tired than I have done for years, and I’m ignoring all sorts of things that need doing.

which sounds like a fair description of my recent state too. That sounds like mild hypometabolism with no other symptoms.

And then it got better (February 2026)

Fatigue-wise things do seem to have got better. Mostly I’m fine, mostly my records say “fine all day”. There have been occasional afternoon naps in the last couple of weeks but they feel tactical as in ‘I have something to do later, I am going to lie down and close my eyes for a while so I have the energy to do it’, rather than ‘Oh God I am shattered and I am going to bed until I feel ok’. Still fatigue, still unusual and a disease I would like to be rid of, but not as bad as it was.

And better again (March 2026), but starting to show hyper symptoms again

Fatigue totally gone, records show a mixture of fine all day, unusually energetic, too hot, and hypomania (which is the state just short of proper mania where you’re really enthusiastic about things and your to do list just disappears). Occasionally feeling tired and going to bed but not able to sleep. Also my morning blood pressure readings are spiking. I am clearly thyrotoxic.

And carried on like that (April 2026):

Three times that week I was tired enough in the afternoon to try going to bed, but then found that I couldn’t sleep and got up again feeling fine. Otherwise I was fine.

At that point I got the train home to visit Mum. I actually felt quite sleepy on the train, but couldn’t sleep and recovered after about half an hour.

And then I once I was home at Mum and Dad’s again I put on a ton of weight as usual, and felt even more tired again, although this time it sounds like that was quite serious hypermetabolism:

Every day I’ve come home tired and most days I’ve gone for a lie down, but I’ve only actually gone to sleep a couple of times. Most days I just lie down for half an hour and then feel fine. At all other times I’ve been quite lively and bouncy, not much trace of fatigue except immediately after walks.

I’ve often been too hot and my waking temperatures have consistently been higher than 36.7C.

Often eating makes me break into sweat, which is not at all normal.

I’ve dropped my thyroid dose in an attempt to control this, and it seems to have helped with the tiredness as well as the overheating. No obvious hypometabolism symptoms so far.

Which tiredness partially fixed itself once I’d stopped taking thyroid, but was still present in the form of post walk attempts to sleep, which I think mostly turned into ‘just lying down for a bit and then feeling ok’:

I’ve basically been forced off the thyroid. Even the tiniest amount now seems to be making me overheat so I’m just not taking it any more, and by my calculations the amount still in my blood is about 1/700th of what was once my daily dose.

Fatigue-wise nothing much happened, still mostly fairly lively, but still getting really tired after going for a walk and needing to lie down, then recovering quickly.

In the same post I actually predicted that I’d lose a lot of weight and feel shattered as a result

At that point I’ll be living on my own considerable body fat, which is still full of PUFAs.

I predict that that will make me feel unwell in various ways, most notably a remarkable increase in fatigue.

And that duly happened, and then seemed to improve slowly (May-June 2026):

The first week back I was about as tired as I’ve been since I first discovered that thyroid would fix my fatigue. It’s more a question of ‘I need to sleep a couple of hours in the afternoon most days’ than ‘full-blown chronic fatigue syndrome’. I never did decide that it was bad enough to go into ketosis, mainly because I’ve been curious as to what would happen if I just left my hands off the controls. The fatigue does seem to be getting better as the weeks go by. I’m still a bit generally sluggish, but although three times this week I’ve felt tired enough to try going to bed, I haven’t actually slept during the day this week at all.

and then it just plateaued at ‘failing to sleep at around 1700 every day’ (June 2026)

the fatigue does seem to be moderating, but it’s still there, mainly manifesting now as a need to go to bed every day at around 1700, but not actually resulting in sleep, just lying down for a bit and then feeling better an hour later. But also periods of sluggishness randomly at other times.

and then I went into a sort of half-hearted version of ex150ish with some carbs in, which has helped but didn’t actually fix the problem:

I do feel much better than I did, but it’s not the usual blinding clarity and inexhaustibility that I get in deep ketosis, and I haven’t seen the “two fuels” problem either. Hypothesise that I still have some carbs around and that means my brain isn’t running entirely on ketones, so I’m still a bit screwed because glycolysis is blocked.

Which is the state I’m currently in, although now I’ve run out of fruit and milk and so I think I’m now going into deeper keto.

That’s about it for fatigue related memories and what I can do by mining my own blog posts.

---

OK, What on Earth?

So I’m currently thinking that the problem here is that something to do with these massive recent weight yo-yos is affecting my metabolism, actually speeding it up and slowing it down, and that I’m failing to adjust my thyroid dose quickly enough to compensate, and so I’ve been alternating between hyper and hypometabolism for the last year or so. And obviously I’m going to blame that on PUFAs because I’m a single-issue monomaniac.

And I’m also noticing that the big drops in thyroid dose have mainly happened in the summer months, which make overheating much more of a problem than it is at other times of year. In winter being a bit warmer than you’d expect is just nice, but in summer it’s actively unpleasant and so you really notice it.

---

A Hypothetical Objective Measure of Fatigue

So if I actually had some objective measure of my fatigue, which I’d been carefully recording all these years, I’d expect it to show:

Vague constant fatigue ever since 2023, which is nevertheless a noticeable improvement on my previous state, which was itself not too bad

In summer 2023, very few afternoon naps or failed afternoon naps

Dramatic improvements in deep ketosis, mild improvements in half-hearted lowish carb diets

Low fatigue levels in the run up to Christmas 2024

Increase in fatigue after Christmas 2024 to the point where I told my boss it was affecting my work (so ‘slightly disabled’ rather than just ‘limited’)

Recovery after that

Massive fatigue August 2025 on, probably explained by thyrotoxicity, getting worse and then better over the period I was home

Massive fatigue early Christmas 2025, explained by sulphite poisoning, but getting better later on

Followed by improvements to the point I felt able to write the fatal words: ‘The almost complete remission of my once-crippling chronic fatigue’

Followed by quite bad hypo-type fatigue, improving and then getting worse as I went hyper again.

Followed by really bad hyper-type fatigue over Easter 2026

Followed by bad hypo-type fatigue, slowly improving until I start being a bit hyper again and get more fatigue.

Eventually leading to my June state of being totally off the thyroid and still irritatingly hot all the time and still fatigued

And finally now, in mild ketosis for a while, fatigue lessening notably to the point where it’s just ‘limiting’ again rather than ‘disabling’.

You can tell I’m feeling better because I’m spending days writing incredibly verbose and tedious blog posts that involved reading lots and lots of other blog posts, and writing computer programs, and other activities which have not looked like much fun recently.

And also I suddenly felt like the eight mile cycle to Burwell and back for supplies looked like it would be fun, and I did it, and I didn’t get tired at all. It felt like when I was young and fit and cycling across France in the heat mainly looking for food, or at least like the last time I was in Wicken Fen for long enough to need supplies, back at the start of all this, and now I do not have to starve to death in the wilderness out of sheer laziness.

---

The reason I am thinking about all this is of course because I have come up with a hopelessly bad method of estimating my fatigue over this period, and I want to check that what I’m looking at makes sense.

But because I’m actually looking at the damned thing right now, and trying to compare what it says with what I remember and wrote, and chasing up anomalies, I can’t help but have fiddled my own results.

So if anyone wants to go trawling through past blog posts to find out where the above story I’m telling is full of shit, now is the time to do it, before I show you what I came up with and it’s not possible to pretend you haven’t seen it any more.

God it would be so nice to have a real mind, where you could just spin off a subprocess that didn’t know something, and get it to do this without cheating. But I am human, this piece of crap is all I’ve got.

1. Which all cleared up quite quickly once I moved back to Cambridge. In hindsight, the fact that I lived opposite an excellent fish-and-chip shop in London and bought an awful lot of their chips seems significant.

2. Full adulthood. I weighed quite a lot less as a eighteen year old student but I was still coming into my adult strength and size for the first half of my twenties.

3. Nutter cycling, I still ride my bike everywhere for transport! But once upon a time I’d ride a forty mile loop fast just for fun.