Whether you want to; lose fat, build muscle, increase strength, increase endurance, or simply be healthy your number one focus must always be nutrition. It acts as both your fuel and aids recovery. You must get an adequate intake of calories through protein, fat, and carbs each day. One of the two most important meals are the ones before and after your workout.
What you eat before exercising determines your energy level throughout the workout, and so can maximize your performance. It is recommended you eat a meal balanced with carbohydrates and some protein around 60-90 minutes prior to exercising. 1-2 hours before your workout have a solid food meal containing a good amount of protein (example foods include chicken, fish, beef, egg whites, etc.), and a good amount of carbs (example foods include, brown rice, oatmeal, or any lower-glycemic source). As you see, nothing complicated or fancy, just stick to basic real food.
The most crucial meal above all is the one you have after your workout. It serves in not only optimizing the results of your workout, but aids you in recovery. The first meal you have post-training replenishes the muscle glycogen that was depleted during your workout and reduces the muscle breakdown caused by exercising. About a a half hour to an hour after exercising you should consume an ideal meal of protein and carbohydrates yet again. However, choose simple carbohydrates, this is the optimum time for your body to really use the carbs instead of store them. Fruits are a great option. If you are on the go, make sure you have prepared a meal or have a whey protein shake along with you. Speaking of fruits, they can also be a quick energy booster prior to your workout, 30 minutes before.
As you can see, the two most crucial macronutrients when you exercise are proteins and carbohydrates, especially after your workout. The meal should be above all fat free. The consumption of essential fats is always overlooked by many and it is crucial to your health and well-being, however, after a workout it is actually counterproductive. Fat slows down the transit through the stomach hence eating it with your protein and carbohydrate may actually slow down the digestion and absorption of both.
To conclude, what matters at the end of every day is to have consumed your adequate caloric intake, it will determine if you gain or lose weight. However, your pre and post workout meals however can most definitely affect your over all results, if you fuel right before and after you train you are more likely to keep a stable energy level and thus exercise more regularly. The more intense your workouts, the more vital it is to emphasize eating pre and post training; eating enough and the right nutrients. I would suggest focusing on making your meals stable and concentrating on making the two meals that revolve around training high in nutrition.