I do understand your goal post comment. It's super-frustrating that virtually all diet information out there has some tangential agenda (Eg. animal welfare, keto/paleo cultism, etc)
I myself did the keto diet and found success with it, but then I transitioned to just more of a selective generalized diet and experienced identical effects. Keto was just the first time I'd ever had a set of rules to apply to the food I ate, which was ultimately the actual training I needed.
However, I did change my diet to be very selective, and felt great. But changing to keto had some additional benefits, the most prominent being a noticeable change in how hungry I felt during the day. It's much easier to go long periods of time without eating when in ketosis.
It also takes a lot of effort to dispel bullshit, much more effort than spreading it. Engaging with flat earthers is exhausting, most people don't do it due to insufficient knowledge and actual scientists don't engage b/c they've got better things to do.
My language is emotionally charged because I've been in the keto community for a long time and I've witnessed a lot of quackery, which I believe can do harm to those in need, just like the anti-vaxers are doing.
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There are very few studies showing the effects of a ketogenic diet on cognition, in healthy subjects.
Here's a study showing that a low-fat diet can have better psychological improvement, versus a low carb diet, even with similar weight loss: https://jamanetwork.com/journals/jamainternalmedicine/articl...
Here's a study that finds similar effects in mood between a low carb and a high carb diet, although the reaction time was improved in the low-fat group: https://academic.oup.com/ajcn/article/86/3/580/4649430
Here's a study comparing cognitive performance between a high carb versus a log carb diet, showing similar results: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC3789132/
Here's one study which merely says that people feel awful for the first two weeks and then start to feel less awful after reintroducing carbs — it's unfortunately not randomized: https://naldc.nal.usda.gov/download/23706/PDF
Here's a study that shows weight loss itself (the biggest confounder of every claim made by keto proponents) is known to affect mood and cognition and to improve quality of life: https://www.ncbi.nlm.nih.gov/pmc/articles/PMC4905696/
Here's one paper arguing that most effects of drugs are attributable to placebo or nocebo: https://www.annualreviews.org/doi/abs/10.1146/annurev-psych-...
People on a diet also tend to do some exercise, here's one arguing about the positive effects of resistance training, which many in the keto community are engaging in: https://jamanetwork.com/journals/jamapsychiatry/article-abst...
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Weight loss, exercise and placebo are actually the best explanations for most of the seemingly miraculous effects of the keto diet.
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Anyway, here's one for the depletion of glycogen: https://science.sciencemag.org/content/254/5031/573.long
Here's a graph showing roughly the evolution of glycogen and ketones during fasting, from "Harper's Biochemistry": https://pbs.twimg.com/media/D-Q0MSPXUAEK_-r?format=jpg&name=...