There’s no strict definition of “low carb.” Some studies suggest that a low-carb diet is any diet with less than 30 percent of calories coming from carbohydrates . A ketogenic diet generally restricts carbohydrates further, to as low as 5 percent of total calories. So while a ketogenic diet is certainly low-carb, not all low-carb diets are ketogenic. The greater restriction of carbohydrates on a ketogenic diet results in the production of ketones.