I'm using a professional at home teeth whitening system (boutique whitening), must I adhere to a strict 'white diet'?

I purchased boutique whitening system from my dentist. It's a 6% hydrogen peroxide gel that's worn in a gum shield of an evening and removed before bed. The dentist said not to eat anything staining for 2 weeks, but one nurse told me they often whiten their teeth and never follow the diet. The thought of subsisting of white rice for 2 weeks with no coffee somewhat scares me- I eat healthily with lots of salad and vegetables. If I whiten at night could I eat non-white foods later on the next day?