A low-carb diet is ideal for an average person - one who has a day job that requires little or no exercise, exercises less than 2 hours a week, or is inactive, such as an invalid.
Most carbohydrates should be eaten during the morning or afternoon, when the calories can be burnt by the body. Eating carbs at night is one main factor of weight gain, because the metabolism is slowing down at the end of the day and isn't ready to face a huge meal, and the carbs aren't used by the body.
The main meal should ideally be in the middle of the day, when it can be used to the body's best advantage.
So no potatoes, rice or pasta at dinner! Unless you are a professional athlete or run marathons, dinner should be made up of water-based high fibre vegetables and a lean source of protein.