BEFORE WORKOUT- Not eating before the workout is something we should never consider because when we are empty stomach our body doesn't have fuel to burn which in turn provides us the energy to perform. Our body uses carbohydrates as fuel during the workouts. It is ideally recommended to eat 60 minutes before starting your exercise and should avoid eating complex carbohydrates and choose a simple form of carbs such as a fruit like banana, apple, or even Greek yogurt. Consuming saturated fats will make digestion slower and make you feel sluggish during the workouts.
AFTER WORKOUT- After a workout, your body needs to be hydrated well and also need to replenish the lost energy by consuming carbs and protein (primarily) within 30-60 minutes. One scoop whey with half banana and hemp seeds is something I prefer after the workout. Your muscles breakdown during the training and to recover it we need to have protein intake necessarily, the before and after a workout, diet is the most important window of building your body.