Training, nutrition and recovery go hand in hand. These are the three pillars of physical performance. While exercise provides a (growth) stimulus, the body has time to make the necessary adaptions during the recovery phase. Of course, in order to make the adaptions, the body needs fuel (energy), tools (micronutrients) and building blocks (proteins), so this is where proper nutrition comes into play. If you want to achieve maximum performance, you have to optimize all three pillars - because you can only make progress when your muscles are fully recovered!