Im thinking about trying the Ketogenic diet because my friend lost a lot of weight on it
I have heard it helps people lose lots of weight, it works by forcing the body to burn fat instead of consuming carbs. Just be careful not to yo-yo. 
Oh can it be dangerous?
Generally not, the most common side effect is constipation which occurs in about 30% of patients. and has a slight increased risk of kidney stones. 
That still doesnt sound fun, but it would be good to lose some weight.
. The ketone bodies pass into the brain and replace glucose as an energy source. An elevated level of ketone bodies in the blood, a state known as ketosis, leads to a reduction in the frequency of epileptic seizures. Around half of children and young people with epilepsy who have tried some form of this diet saw the number of seizures drop by at least half, and the effect persists even after discontinuing the diet. Some evidence indicates that adults with epilepsy may benefit from the diet, and that a less strict regimen
have shown that it is not possible to reduce fat in one area by exercising that body part alone. Muscle growth in a region does not reduce fat in that region. Instead, fat is lost from the entire body as a result of diet and regular exercise.
Research.
All body shapes are different, meaning, people carry fat in different places. Some locations on the body are more metabolically active than others, and those areas will lose weight quicker than those that are not as metabolically active. For many