Plasma protein concentrations, in particular the serum albumin concentration, are often quoted as indicators of nutritional state in surgical patients. Injury also affects the circulating concentrations of these proteins. Twenty students were subjected to a 3-day total fast and the concentration of plasma proteins, generally affected by trauma, determined before and after the fast. The only protein to show any negative response was retinal binding protein which fell by 16% during the starvation period (p < 0.001). Albumin, the protein often used as a nutritional index, demonstrated a significant (p < 0.001) increase during this period. This was not related to changes in the hydration state of the subjects.