If you are trying to build body mass, then you should definitely work out for losing a lot of fat and gaining mass. The less fat you put on during this phase, the easier it gets tone your muscles. You can also follow the best mass building workout programs that are available online. One such genuine and reliable portal is Ryan Spiteri.
Your carbohydrates intake should always fall during breakfast and your workout window (pre and post).
Avoid consuming carbs before you sleep.
You should have higher GI (Glycemic Index; your insulin response when you consume carbohydrates) post-workout and low GI at any other times.
Include salad in every meal.
Here's a list of carbohydrates sorted by GI and suggested by mass building workout programs -
High GI food: white bread, sugary bakeries, white rice, corn syrup
Low GI food: brown rice, oatmeal, apple, whole grain bread, sweet potatoes, yams, all sorts of vegetables.
Fats: About 10% of your daily calories should come from healthy fats (unsaturated) such as almonds, salmons, olive oil, avocado and tofu.