To maintain adecuate sugar levels, the metabolism awake and optimal energy levels, the best thing is to eat five times a day in small quantities.  The combination that works best for me is this:

 -Breakfast: One protein + one carbohydrate (fruit, whole wheat bread, cereal) + una portion oil/grease (butter, cooking oil, nuts, avocado).

-Mid morning snack: Either a fruit, cheese, or vegetables (cucumber, tomato juice, vegetables, etc.)

-Lunch: One protein (chicken, meat, fish, tofu) + one carbohydrate (bread, rice, beans, legumes, sweet vegetables like corn, carrots, potatoes) + one portion grease (cooking oil, oive oil as dressing, avocado, nuts).

Mid afternoon: A snack, as in mid morning, it can also be a healthy dessert, like a glass of milk with a whole wheat cookie or dark chocolate.

-Dinner: One protein (eggs, milk, cheese, ham,etc.) + one carbohydrate + one portion of oil/grease.

This combination keeps the sugar levels stable throughout the day, achieving a constant energy output.  Besides, eating five times a day keeps the metabolism running all the time, which also keeps up the energy levels and burns calories, which helps reduce weight.