..............short fasting might even help the brain learn: The effects of food deprivation and incentive motivation on blood glucose levels and cognitive function. Psychopharmacology (Berl). 1997 Nov;134(1):88-94. Green MW, Elliman NA, Rogers PJ. Consumer Sciences Department, Institute of Food Research, Reading, UK. 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. Food deprivation induced parallel changes in blood glucose, plasma free fatty acids and feeding during two parts of the diurnal cycle in rats. Neurosci Biobehav Rev. 1980;4 Suppl 1:17-23. Le Magnen J, Devos M, Larue-Achagiotis C. The changes in plasma glucose and free fatty acid levels and in subsequent feeding induced by 4 to 10 hr of food deprivation were investigated in rats and compared for the two parts of the diurnal cycle. It was found that increasing fast duration at night induced a more rapid fall of plasma glucose and elevation of plasma free fatty acids than in the day. However, a similar increment of the first post fast meal was elicited by an identical decrement of blood glucose level for the two periods except after a 10 hr fast during the day. The acute effect of darkness and light per se being experimentally excluded, it was concluded that the size of the first meal following short term food deprivation was dependent throughout the diurnal cycle on the fast induced glucoprivic condition.