My DD has been doing Keto for the last several months and has lost about 65 lbs. She looks fantastic and says she feels fantastic too. But it is more than just discipline. It is understanding how your body uses the food you eat. As far as the 'Keto flu' feeling, it means that your body needs electrolytes--a shot of pickle juice is what she would take if she felt that way. Believe it or not, salt and fat are good when carbs are severely limited. Again it is the 'right' fats that are key. Keto is also the only diet that has been scientifically proven to reverse stage 2 diabetes.
But before you just cut all carbs from your diet and start chowing down on steak and bacon, do more research and absolutely talk to a doctor if you have any health issues.