To learn more about dim sum, click here. http://chinesefood.about.com/library/weekly/aa070700a.htm
Originally a Cantonese custom, dim sum is inextricably linked to the Chinese tradition of "yum cha" or drinking tea. Travelers journeying along the famous Silk Road needed a place to rest, so teahouses began springing up along the roadside. Rural farmers, exhausted after long hours working in the fields, would also head to the local teahouse for an afternoon of tea and relaxing conversation.
Still, it took several centuries for the culinary art of dim sum to develop. It was originally considered inappropriate to combine tea with food - in fact a famous 3rd century Imperial physician claimed this would lead to excessive weight gain. However, as tea's ability to aid in digestion and cleanse the palate became known, tea house proprietors began adding a variety of snacks, and the tradition of dim sum was born.