Food withdrawal provides a very powerful way of adapting behaviour of the model organism C. elegans (Hill et al.). Indeed, previous work has highlighted that worms are considered starved when cultivated in the absence of food for 2 hours. We have recently noted an adaptive response of the muscle organ, the pharynx, following withdrawal of food. Investigation of developmentally staged worms (L4 plus 16 hours) that were deprived of food showed differential regulation of feeding behaviour to the absence of food over time. Feeding behaviour was quantified by counting the pumping, i.e. the movement of a grinder (visible as a black line in the pharynx). This paradigm sees three phases of behaviour i. the initial cessation in pumping is followed by a slow increase in pumping until it reaches a ii. steady state pump rate (~50 pumps/min) after 70mins. After this initial plateau, which persists for approximately one hour, the worms undergo a series of erratic pumps in which they are relatively quiescent or pump at the high frequency similar to seen in the presence of food. This latter phase is quantified by the increased variation in pump rates. Although, previous investigations have defined removal from food for 5 hours as starvation (Avery et al.), our investigations of the nutritional status show that the worms retain their lipid stores during the initial 5 hours (Sudan Black staining), indicating that they may not be starved. However, after 10hrs there is a decrease in fat staining in the head region of the worms as measured by pixel density, from 1180862 (n=14) to 739853 (n=19) pixels (P<0.0001, t-test). The microcircuit that controls pharyngeal pumping is made up of 20 embedded neurons and a single neuron contact to the extra-pharyngeal nervous system. This circuit is underpinned by a number of fast and neuromodulatory transmitters, whose homologues regulate feeding behaviour in mammals. Analysing mutants that define key transmitters within this circuit helps define the locus for the neuroadaption and the cellular and molecular determinants of the behaviour. E.g., although serotonin is a key regulator of the worm’s response to the presence of food, it does not play a role in the adaptive response to the food deprivation. This work should provide a framework to investigate microcircuits that define model feeding behaviour and the modulation to varying nutritional states of the organism.