[rotwoof]

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.