Believe it or not, most people don't eat as much food as they should. I'm not talking about those people who go out and eat fast food all day long, but a lot of people simply don't eat as often as they should throughout the course of the day. If you start to think of your body more like a car and your food more like the fuel you need to drive that car, you'll realize that you need to provide your body with not only the right fuel, but the right amount of fuel at the right time and that is what a good weight training diet is all about.
You wouldn't go and fill your gas tank up when it's already full would you? Yet so many people will eat way more at one time then they really need or want. Instead only add fuel to 'your tank' when you're tank starts getting low. Most people wouldn't add some low quality fuel that their neighbor just made in their garage either. Yet many people will load their body up with all kinds of bad things, all misleadingly labeled as food.
Make sure you don't get conned into spending a lot of money on some pill that is supposed to make you lose weight either. There may be some helpful supplements available, but they will never take the place of a sensible diet and exercise plan.
When you are eating post workout your weight training diet should basically reverse the types of foods that you eat. For example, most meals will consist of low glycemic carbs, a lot of healthy fats and slow release protein. This combination can help you stay full longer. After a workout you want to feed your muscles to encourage maximum growth so you should eat a meal that has high glycemic carbs, very little fat and quickly digestible proteins.
Treat your body like the finely tuned machine it was meant to be. Only provide it with the best weight training diet. A good diet will have enough proteins, carbs, and fats and will provide your body with the high quality fuel it needs to run at it's peak for a long, long time.