If you are into the sport of bodybuilding, and are looking to pump up quickly, or trying to get into the best shape to be able to compete (either in an amateur setting or professionally), not only will you have to follow the strictest workout regime, you will also have to eat the right foods, and follow the right diet in order to get into the best possible shape. Although many bodybuilders use illegal drugs, this is not required to get your body looking its best, in fact over a long period of extended use, these will cause more harm than help, so avoid them at all costs.
As far as diet and bodybuilding nutrition, you must follow an extremely high protein, low carb, and low fat diet style in order to get a ripped body, and the quickest results when training for a competition. Eating high protein foods including lean meats, egg whites, and other high protein foods is the best way to build lean muscle. You should aim for at least 25 grams of protein per meal (depending on your size, body weight, and gender), in order to get the leanest muscle build quickly. Also incorporating high protein shakes and powders (such as whey isolate, egg based protein, and whey powder) to make a shake or smoothie is a great way to get high protein, low fat, low carbs, and low calorie. Another great product to use for protein intake are protein bars (usually those that say carb conscious or low carbs); they are packed with protein and can keep you full and fueled for a long and intense workout, or can be used post-workout to rebuild any lost nutrients.
As far as carbs and fat, you must really cut back on both. Carbs, such as brown rice, potatoes, fruits are vegetables are much better then wheat based products. But, even so, they must be eaten sparingly. As far as fat, a little is necessary, but avoid saturated fats as much as possible, and when possible look for fat free food options as well.
Although your workouts are the biggest "piece of the puzzle," eating the right foods, and cutting out certain foods which offer no health benefits to you, is essential to ensure that you are getting the right calories into your system.
For more information checkout the Bodybuilding Cookbook.
Bodybuilding Nutrition Guide