Hello - I think I can help here, because I am about a month ahead of you on a similar path for a health condition (not PCOS).
In general, people here advise against number chasing and explain that ketones over 0.5 are in ketosis - but when it comes to seeking for a high GKI ratio or a low Dr Boz ratio, then you are looking to raise ketones higher.
I can confidently say that your doctor has given you perfect advice, because I was in the same position as you - someone who’s been eating this way long term, and when I tested in a morning, my glucose was around 4.6 and my ketones around 0.8.
Like you, I was eating minimal carbs, having a small eating window etc - and I was quite surprised at the results.
I changed my macros to an 80/20 fat/protein ratio at the start of this year, and now my glucose averages 3.8 and my ketones average 3.2.
It took about 2 weeks of eating 80/20 to see an impact on the glucose/ketone meters.
You may find that you are ravenously hungry when you first start - and that might be contributing to you feeling tired and lethargic. If the theory of being fuelled by glucose-from-protein is correct, then it makes sense that we feel a bit rubbish as we move back to prioritising fat.
For me, this manifested in - no joke - an extra 1000 calories or more a day (I was eating around 2200 a day last year, settling between 1800-2500 depending on what I was doing in the gym. At first, doing this, I was eating around 3300 - now I eat - I double checked here…I do get up to 3300 some days still, but my average overall is 2700 - and I am currently sedentary through illness).
But before you get super scared because I know that calorie figure looks massive, I have lost size over the past month - and as stated, I am sedentary. So if I’m burning through 2700 calories, if you’re going to the gym and living an active life, you will likely be doing the same and/or more.
One of the keys with 80/20 eating seems to be reducing your protein per meal. This has been a huge shift for me and it takes some doing psychologically. I am carnivore, so I was used to sitting down with a steak and eating it. Now, it means having a small portion (maybe 125g) and having fat alongside it (tallow, butter etc) and perhaps something with a higher f/p ratio, e.g. cheese - or even a decaf coffee with dairy in it. (Some in the carnivore space have buttery water, omitting the coffee entirely - I’ve not tried this yet).
This was a huge deal for me because I’d not eaten dairy for 2 years! And suddenly, instead of a massive plate of food that I was accustomed to, I have a tiny side plate with barely anything on it and a big portion of it is dairy.
Eat the fat first. For me, I start by having a couple of fatty decaf coffees and then I eat my first meal maybe an hour or so later - and the fat from the coffee is already starting to satiate me. Then eat the fat from the plate first, if you can, and then eat the protein.
Another thing to watch for is that you do get full but the signal is so delayed. So sometimes you finish a meal, still feel hungry and you contemplate getting something else. Give it half an hour - usually within half an hour, I’ve realised I am full. If I try something else, 90% of the time, I realise too late that I am actually stuffed and any extra makes me feel queasy. If it’s been an hour and you’re still hungry, have some more fat - sometimes I have a bit of whipped cream or a bit of butter or something, and that usually stops the feeling in its tracks.
Also, don’t try to stick to an eating window - especially at first. Eat when you’re hungry. I was eating in a 5 or 6 hour window last year - naturally, not forced. I changed to 80/20 and for a while, I was eating much more often - in more of an 11 hour window. Just go with it and trust your hunger signals.
Sorry this is long but I really feel for you and I recognise myself a month ago. 80/20 is very different, but I feel a lot better doing it. It’s still weird not to just cook a steak and eat the lot, but it has also saved me a fortune on buying meat!