A person described as being overly critical of other people's meal choices. Nutrition Nazis will often express their displeasure with someone's choice of food that they deem unhealthy or unfit for human consumption. Some might even advocate for everyone to be forced to have their meals meet the Nutrition Nazi's standards.
Father: You know, I heard that teachers are taking away kid's lunches because they thought it wasn't healthy enough.
Mother: Really? Those people are total Nutrition Nazis!
A trip to a grocery store, convenience store, or gas station for the sole purpose of buying an excessive amount of junk food and sugary drinks, usually with friends. A chud run often happens late at night and ends with everyone involved hating themselves afterwards.