Many health experts stress the importance of eating a good breakfast and having one's main meal earlier in the day.There is a saying：Breakfast like a king，lunch like a prince and dinner like a pauper(穷人)．This means that breakfast should be the largest meal of the day.Why? Because the food you eat for breakfast will give you energy to use while you are active during the day.There is evidence that eating a big breakfast，particularly one containing grains and fruit，can improve your concentration and mood.