Diet is extremely important :/
Maybe not for just starting out but once you get past beginner gains and strength you start hitting plateaus etc.
Your central nervous system gets you stronger by recruiting high threshold motor units,
But if you eat insuffiently and run out of more msucle fibres to get stronger...what more can your CNS do?
Just eat heaps of protein, healthy fats carbs in the morning and after your workout.
Max 2 hours after your workout eat a post workout meal, which replenishes your carbs that you've used during that workout otherwise you'll use protein from muscles to replenish those carbs your body desires.
I'm pretty sure it goes like this... the day befores diet depends on your workout today?