The current study investigated the relationships between blood glucose levels, mild food deprivation, sympathetic arousal, and cognitive processing efficiency. Subjects (n = 82) were randomly assigned to four experimental conditions, comprising combined manipulations of food deprivation and incentive motivation. Baseline and mid-session measurements of blood glucose, blood pressure and pulse rate were taken. Subjects completed a number of measures of cognitive processing efficiency and self report measures of affective and somatic state. Although glucose levels were lowered following food deprivation, there was no significant detrimental effect of food deprivation on task performance. However, improved recognition memory processing times were associated with deprivation. Incentive motivation was associated with faster simple reaction times and higher diastolic blood pressure. There were no significant relationships between glucose levels and task performance, further supporting the hypothesis that the brain is relatively invulnerable to short food deprivation.