Carbohydrates have gotten alot of good and bad press over the years and confusion runs high as to what carbs are and what do they actually do? There are High carbs diets, low carb diets, zero carb diets and everything in between. Carbs are basically all the good stuff, the yummy stuff, such as, Breads, Cereals, Fruit, Rice, Pasta, Potatoes - they are good carb sources. Chocolate, Sugar, Honey, Juice Drinks, Soft Drinks, Crisps, Savoury snacks - those are bad carb sources. 

Carbs are basically a fuel source for the body to supply energy for daily activities, exercise and concentration. Your body does need a certain amount of carbs daily but, if your intake is too high then it will lead to the accumulation of bodyfat. If you are under weight and need to gain bulk weight then you will need an excess of carbs but if your looking to reduce your bodyfat then you must regulate the overall amount of carb intake per day, generally reducing portion sizes and cutting out the bad carbohydrate sources. 

If your goal is to reduce bodyfat I recommend 1.5-2g of carbs (from good carbs) per Kilo of lean body weight per day (lean body weight can be measured via bodyfat testing) If your goal is to gain weight or bulk up then you can get away with higher intake of carbs such as 3-4g of carbs per kilo of lean body weight per day. You must also factor in daily activity levels such as, how much exercise are you doing per day? is your job sedentary or demanding? marathon training or just walking? If your lifestyle is demanding then you might be able to get a way with some extra carbohydrate in your diet but if not then you must be more strict with your intake of carbs. You really have to deserve your carbs, otherwise you will be wearing them instead of burning them off

- APG