A low-carbohydrate diet means that you mainly eat proteins and fats. Bread, rice, pasta and potatoes are no longer allowed. The diet is based on the fact that your body gets energy from fats and proteins instead of from fast carbohydrates. This puts your body in ketosis, causing you to burn more fat and eventually lose fat.
A low-carbohydrate diet is so efficient because the proteins you eat do not break down muscles if you consume fewer calories. In addition, you can deduct about 20% – 30% from each protein calorie, because your body uses more energy to convert the proteins into usable energy for the body. If you eat 100 kCal of protein, it will effectively only provide 70 – 80 kCal of energy. Finally, proteins and fats ensure that you feel full for longer, so that you have less appetite during the day. It allows you to ignore all that goodness.
A low-carbohydrate diet therefore means that you leave almost all carbohydrates. Eating no carbohydrates at all is impossible. A low-carbohydrate diet is referred to when less than 10% of the energy requirement is obtained from carbohydrates. That 10% does not consist of refined sugars, but of carbohydrates that are extracted from the vegetables you eat. You also have a slow-carb diet, where you are allowed to eat certain legumes, because these carbohydrates are released slowly, they do not cause insulin spikes.