It seems that we just don't have enough time to plan meals. I hear this complaint from busy professionals all the time. There are actually many benefits to meal planning. Planning meals helps you think about what to eat before you are hungry. If you plan ahead, your family will also be more likely to get the variety of foods and nutrients they need each day.
Planning actually saves time and money.
Think of a main dish. Relying on the food groups. For each meal use foods from at least three different food groups. A menu could be, for example, cold cereal with peaches and low fat milk. Planning for variety.