I was asked “what should I before exercise” by my students.
You don’t want to be too full nor too hungry. It takes 2-3 hours to digest foods so generally recommend to have a meal two hours before you exercise.
Typical breakfast in North America are:
Bowl of fruits
Toasts and eggs
Personally, I like variety in what I eat for breakfast, for example:
A bowl of brown rice, raw egg, radish leaves (cooked with soy source and sesame oil) and sea weeds before strength class.
A bowl of soup (Fall/Winter) or smoothie (Spring/Summer) before cardio class, something easy to digest.
Yogurt (with chia seeds and maple syrup), Kiwi, Apple, Blue Cheese, Pate (duck) and boiled egg.
Try to eat variety of food instead of just toast or bowl of cereal.
Listen your body. Your level of activity may be different every day so from time-to-time, your body may need a different selection food.