A young actress died of kidney failure and the reports say that the doctors feel that keto diet is the reason behind her kidney failure. Now we do not know what the fact is, but let us take a look at what a keto diet is and whether it is healthy or risky?
The term keto diet has come from the word "ketogenic" which means a low-carb diet. This diet says that you get more calories from protein and fats, and less from the carbohydrates which means that you cut on the carbs that are easy to digest.

When you eat less than 50 grams of carbs a day, your body eventually runs out of fuel (blood sugar) it can use quickly. This typically takes 3 to 4 days. Then you’ll start to break down protein and fat for energy, which can make you lose weight. This is called ketosis. It's important to note that the ketogenic diet is a short term diet that's focussed on weight loss rather than the pursuit of health benefits. (This is what most of the sites talk about it and we have copied this from the source).

A keto diet is used to lose weight (mostly used by actors, sportsmen, and people from the media industry), but you must consult your doctor before taking this diet. The health benefits are that it may help people with heart disease, epilepsy, some brain diseases but researches are being done to these areas so it is highly recommended that the person taking this diet must first consult a doctor. 

The not-so-serious side effects as known are conspitation, low blood sugar, indigestion, bad breath, fatigue, headaches and of course weakness. Now here is the other side of coin...when the body burns the fat, it can really be bad for the kidneys. From being obese and having other health problems to trying keto diet and then cutting it can be a very tricky situation. So if anyone who wants to stop the keto diet, he MUST take advice and cut the diet slowly based on a doctor's instructions. A drastic cut down on your own can cause you your life. 
(The article has been taken from various sources and modified for simplification)

PLEASE DO CONSULT YOUR DOCTOR BEFORE YOU START ANY KIND OF DIET OR EVEN A CRASH DIET BECAUSE ULTIMATELY EXCESS OF EVERYTHING IS BAD.