If you are having a hard time losing weight and gaining lean muscle mass then I would highly suggest you consider implementing a solid nutrition plan into your workout routine. Nutrition is one of the most overlooked and heavily regulated areas of personal training and bodybuilding, but is arguably the most important aspect of fitness. The lack of proper nutrition can cause many problems in both your training sessions and in your life at large. Even if you have the best workout in the world, if you are not eating right then you are not going to experience the results that you desire.
The first step to understanding nutrition is learning what it is, how it affects you, and how to put it to use. The most important aspect of nutrition is your daily diet. Your nutrition plan should be centered around foods that are high in protein, carbohydrates, and calories. Your diet should consist of these food groups at each meal, and you should eat a smaller amount of fats each day than you do today. The goal with your diet is to create an ideal eating situation where you create a calorie deficit (the opposite of your calorie intake), and burn off more calories than you take in.
Another important factor to remember with nutrition is how much you eat. Bodybuilders who get fat easily because their diets are so bad are missing out on the most important aspect of bodybuilding, metabolism. When your metabolism rate is high, you are burning more calories all day long, even when you are at rest. This allows for a natural boost in muscle growth when the next meal or workout comes. A well-balanced diet, consisting of the right combination of carbs, proteins, and fats will go a long way toward helping you achieve your bodybuilding goals.