Restricting your carbohydrate intake down to 5% is completely unnecessary and very restrictive. There is absolutely nothing wrong with carbohydrates in general, simply certain types of carbohydrates people should avoid. Things like fruit, vegetables, whole grains and legumes are incredibly good for you. Essentially, people should strive for more of a whole food type diet and avoid processed foods. The biggest issues with the keto diet relate to fiber intake and Ketoacidosis. People in general, but specifically Americans, are already fiber deficient. As an adult male you should take in about 38g of fiber per day (women should get about 25). If you follow a keto diet as intended and run a 2000 Calorie diet, at 5% carbs, you would consume about 100 Calories which equates to 25g (carbs). It is physically impossible to get the daily fiber requirement of 38g when you are only consuming 25g of Carbohydrates (unless you supplement). Regarding being in a state of Ketosis, that is acceptable but not advised for long periods due to the impact it has on blood pH levels and hormone production. Not to mention, you are essentially teetering on the line of Ketoacidosis which can be detrimental and even fatal.
I will say without a doubt, doing the keto diet is better than being 100lbs overweight. No argument there. If it is optimal health you are striving for along with weightloss, the keto diet is not a good option. Simply reduce your calories, strive for balanced meals and try to eat a diverse spectrum of whole foods.