The effects of food deprivation and incentive motivation on blood glucose levels and cognitive function

Abstract

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.

Effects of Fasting During Ramadan Month on Cognitive Function in Muslim Athletes

“…This is consistent with our findings of a lack of any significant performance decline in the non-speed dependent, predominantly occipital cortex centred one-card learning and one-back memory tasks, which supports the previously demonstrated robustness of these domains [15–17,22] .…”

The effect of weight-loss dieting on cognitive performance and psychological well-being in overweight women

“…However, other studies have shown that missing one or two meals, or fasting for 24 hours causes no consistent detriment in complex cognitive performance. Furthermore, Green et al (1997b) found no relationship between lowered glucose levels as a consequence of missing a meal and cognitive performance. They concluded that the results do not support the proposition that dieting affects cognition via an impact on glucose levels.…”

Nutritional influences on cognitive function: mechanisms of susceptibility

“…Adrenergic antagonists oppose the effects of arousal, but not glucose, on memory (Nielson & Jensen, 1994;Gold, 1995). Furthermore, it has been found that, whereas manipulating arousal levels by means of incentive motivation does produce selective improvements in performance, those improvements are unrelated to blood glucose levels (Green et al 1997a). Indeed, sympathoadrenal arousal during a psychologically challenging performance test does not necessarily lead to any change in plasma glucose in the absence of intake (Hagström-Toft et al 1993).…”

“…A recent meal may interact with the impact of arousal on blood glucose as well as with the effect of further glucose intake (Martin & Benton, 1999). Moreover, fasting has been associated with enhanced speed of performance on memory tasks in some studies (Benton & Owens, 1993;Green et al 1997a), but poorer recall levels in others (Martin & Benton, 1999).…”

“…Furthermore, plasma glucose level after the load predicted the extent of stressinduced rise in cortisol, whereas in the absence of stress, cortisol did not change following the glucose load . This dependence of a stress-induced rise in cortisol on the non-deprived state might help explain improved performance on certain tasks in children who missed breakfast, and in overnight fasted adults, in whom speed of performance on memory tasks was enhanced (Benton & Owens, 1993;Green et al 1997a): perhaps those outcomes particularly benefited from a lack of cortisol release during the tests.…”