The term "negative nitrogen balance" refers to a state in which an individual or animal is losing more protein than they are taking in, resulting in a deficit. Full definition
About three hours after a meal, we begin to «burn» muscle protein (instead of bloodstream protein) and our bodies go into negative nitrogen balance. (lasting-weight-loss.com)
Negative nitrogen balance occurs when your nitrogen intake is not sufficient to cover your nitrogen needs. (thomasdelauer.com)
Metabolism 12:259 - 274), 5 of 10 athletes were still in negative nitrogen balance even while consuming 250 % of the RDA. (bodybuildingforyou.com)