If you're watching your weight, avoid eating after 7:00 pm. The digestive system is at its lowest energy level after this time, until morning. From a Traditional Chinese Medicine perspective, eating late can cause indigestion, food stagnation in the intestines, and promote phlegm formation and disorders (including tumors and cysts), insomnia, obesity, and circulatory diseases. It is a major cause of morning sluggishness and lack of appetite (for breakfast). If you eat three meals a day and fast after 7:00 pm, you are more likely to wake up with a hearty appetite for the morning meal.
(Source: Herbs for Health: Being Well the Natural Way Magazine, Jan/Feb 2003)