I always fly from Beijing to Toronto (at least 2 times a year) and I live in Tianjin which means I need to take train to go to Beijing.
My experience tells me you should not take any foods or drinks with you if possible. There will be some possibilities that you won't be found if you put the foods in the checked baggage (I have done that many times). However, don't do that at the very first time as it may sometimes cause problem.