In addition to working out hard and using the right supplements, what nutritional advice can you give me to help build muscle and burn fat?
The first thing you want to make sure you're doing is consuming meals that are balanced in protein and carbohydrates six times a day. A bowl of pasta is not a "meal"--neither is 15 egg whites.
I believe there's a certain metabolic environment created when you consume a nutrient-rich, calorie-compact meal containing protein and carbohydrates that is important for optimal amino acid and energy uptake by your muscle cells as well as proper oxidation (burning) of fat.
As far as calories go, if you're trying to build muscle and burn fat (which is basically what I'm always trying to do), I recommend consuming a number of calories equal to your body weight times 12. For example, I weigh 200 pounds, so I try to consume around 2,400 or 2,500 calories a day (200 x 12).
If your main focus is to try to get cut, I recommend planning your daily calorie intake around a number equal to your body weight times 10. For example, if I wanted to get really cut and not focus on gaining any more muscle size and strength for the time being, I would try to consume around 2,000 calories a day (200 x 10).
Now, if you're trying to "bulk up" and you aren't concerned with fat loss, I recommend consuming a number of calories equal to your body weight times 15. For example, if I just wanted to put on more muscle size and strength and was not concerned with losing fat (or even gaining a little), I would consume 3,000 a day (200 x 15).
I recommend a diet that consists of around 30% to 35% protein, 45% to 50% carbs, and around 20% fat. (Yes, 20% fat! Some dietary fat may be necessary to build muscle size and strength. If you don't believe me, try to get bigger and stronger without it! If you lower your fat intake down to 10% a day or less... within a week you'll probably notice a decrease in strength and muscle fullness.)
The number of calories you're planning to consume each day should be divided by the number of meals you're going to eat. For example, if my goal intake is 2,500 calories a day (which it is) and I plan on eating 6 meals, that means I should be trying to get around 400 calories per meal (give or take 100).
You can get your calories from quality whole-food sources like oatmeal, chicken, turkey, cottage cheese, pasta, skim milk, reduced-fat cheese, lean steak, all kinds of fruits and vegetables, or you can use a high-quality meal-replacement powder or protein supplement.
You should also drink a lot of water each day. I try to drink at least 60 ounces of water--not pop, not milk, not juice--just water. (Water is absorbed by your system differently than calorie-containing fluids.) This is to be consumed in addition to any water that might be used to make protein drinks or anything like that. This water can be consumed with meals or between meals. Drinking a lot of water helps keep your muscles properly hydrated (full of water), which is very important on any muscle size and strength-building program.
Now, the above recommendations are "guidelines," not "etched-in-stone" rules. You might be one of the rare people whose metabolism is so fast you need to eat more calories per day than what I'm recommending. If this is the case, try starting with one of the "baseline" numbers I recommended above and increase the number of calories you eat by 500 a day for one week. Then, make an evaluation--gradually "fine tune" your calorie intake until you think you're getting the desired results. (It's extremely helpful to keep a "nutrition log"--especially if you're not really sure how many calories you're taking in each day.)
Now, if you're one of the rare individuals whose metabolism is especially slow, you may have to decrease your calorie intake by 300 calories a day, a week at a time, until you start to see the results you desire.
Give these recommendations a try--I'll bet you'll see a difference!