Just eat real food.
Meat except Pork (chicken especially)
Veg (more than fruit)
Real carbs i.e wholemeal bread, potatoes, pasta.
Don't drink too much juice, solid fruit is much better and you should have as much water as possible.
Nothing processed, nothing with lots of fat, and nothing with lots of salt or sugar.
You don't need a structured diet, just eat what's healthy and reject what's not, it won't take long to get used to it.