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.  
I think the diet was originally for treating epilepsy patients, because it seems to reduce seizures by half in young people and children. Still good for weight lose though.
Thats amazing that it was able to help people like that.  Science is so cool sometimes
Ketogenic diet
The ketogenic diet is a high-fat, adequate-protein, low-carbohydrate diet that in medicine is used primarily to treat difficult-to-control (refractory) epilepsy in children. The diet forces the body to burn fats rather than carbohydrates. Normally, the carbohydrates contained in food are converted into glucose, which is then transported around the body and is particularly important in fueling brain function. However, if little carbohydrate remains in the diet, the liver converts fat into fatty acids and ketone bodies
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