I know it's mentioned in the article for long term but for the first couple weeks was there any difference in brain functioning? I'm not talking about anything severe, but if you have a job where you are using a lot of brain power, I'd imagine very low carb diet seems to be a little counter-intuitive. Like the article said the brain gets energy from ketones but is it the same amount/enough energy as regular carbs? Do you feel slightly slower, possibly more tired when performing longer challenging tasks? I've dieted very strictly before with a lack of carbs but also a huge deficit of calories and couldn't think nearly as quick. I agree lack of calories was the primary reason for this but it also seems very low carbs could contribute to constraining optimal brain output.
If anything it's easier to stay mentally alert for longer periods of time on Keto. The body manufactures enough glucose to supply the brain with what it needs on its own, the remaining nutrient needs are covered by ketones which are produced in the liver.
If you have any significant stores of body fat (15-18% body fat is the ideal for males, ~18-20% for females) your body is expending those fat stores in order to supply itself with the energy it needs. This makes it easier to stay calorie-deficient while on keto. During the past 7 months I've easily stayed calorie-deficient 80% of the time or more. I never go hungry, I eat whenever I'm hungry, I eat until I'm full and when I tally up the calories that usually puts me at or below 1500 daily calories.
Now this was the weirdest part of keto for me: When I'm doing intermittent fasting regularly I experience the most significant cognitive improvements.
There's something called 'keto flu' where for the first week or two you can feel a little off while adjusting, but afterwards you have plenty of mental energy, as long as you keep your electrolytes up.
All previous diets for me failed because I always felt like I couldn't think and do my job and needed to flood my system with calories in order to keep going... on keto I haven't had that feeling even once.
When I first went keto, I didn't experience any brain fog, but what was distinctly different was that I had a crazy amount of nervous energy, slept really well for the first time in years, and felt refreshed on 4-5 hours' sleep for the first couple of weeks. I lost 13 lbs. (probably 90% fluids) in the first 2 days... then nothing more for a month.
