When the culprit is doctoring the Protein bar, the back of the wrapper has the obligatory list of ingredients: "LARK'S VOMIT" (a Monty Python reference), and "INULIN (NOW JUST WHAT THE HELL IS THAT)" are both listed.
When Catherine and Grissom are looking through the dead runners bag, Grissom remarks on the rubbish and Catherine tells him there is a 5 minute penalty for anyone caught littering along the race course. However, at the very beginning of the episode, Nick is seen grabbing a bottle of water, drinking a little of it and then throwing it away on the side of the road.