Anyone know what is a low carbohydrate diet?

See below: A carbohydrate is a molecule made of carbon, hydrogen, and oxygen which are chained together. Another term is a saccharide, or more commonly, a sugar. Complex molecule chains of saccharides are called complex carbohydrates or starches. In common usage, a "carb" is used for a food which has a high content of carbohydrates. A "low carb diet" would be a diet low in carbs and high in protein and fat.

See below: The term "low-carbohydrate diet" is generally applied to diets that restrict carbohydrates to less than 20% of caloric intake, but can also refer to diets that simply restrict or limit carbohydrates to less than recommended proportions (generally less than 45% of total energy coming from carbohydrates)