Will water fasting cause any negative effects on my mental capacity to perform critical thinking or solving math problems like calculus?
During the beginning phases of your fast, your mind might be a little bit cloudy. However as you progress and your body enters ketosis (usually around the 3rd -4th day) many people report having enhanced mental clarity.
If you are coming from a carb-fueled diet, you might get some fog. Keeping up on electrolytes will ease that somewhat. The fat-fueled brain is pretty much clear and focused always- at least that’s been my experience over the former.