I've written in previous post why the keto diet is dangerous to the body but did you know you can actually become ill when trying the diet? It is called the "Keto flu". What do the symptoms look like?
Why does this happen? Because your body is burning its fat reserves instead of carbohydrates. Now, you may think that burning those fat reserves is a great way to lose weight, but it is also dangerous because your body needs those reserves if your body is ever truly starving. Do you know who else puts their body's into ketosis- those who suffer from anorexia nervosa. It is not healthy to put your body into the same state as those who suffer from a starving disease.
Dehydration can be one of the more dangerous states for the body. "For every gram of glycogen (the fat reserves you burn in ketosis) you burn you lose three grams of water" Carbohydrates store water that your body needs. Your kidneys especially need the water that carbohydrates store. This dehydrated state also effects the liver and muscles because water also helps to retain vitamins and minerals that your body needs. If you aren't taking in carbohydrates then your body isn't retaining all of those vitamins and minerals.
Finally, your brain runs off of carbs. If you cut out the carbs then your body has to use other sources to function properly. When your brain cannot get the glucose it needs you wont feel as quick, you may feel a brain fog, head aches, and confusion.