Circulating blood glucose levels affect desire for high-calorie foods

Aliki Kosteli, University of Cambridge School of Clinical Medicine, Addenbrooke's Hospital, Hills Road, Cambridge, CB2 0SP

In this month’s JCI issue Page et al. show that mild hypoglycaemic conditions that commonly occur several hours after a meal in healthy individuals activate brain reward and motivation pathways, while increasing the desire for high-calorie foods. The authors used functional MRI studies (fMRI) to investigate how a circulating blood glucose reduction affects responses to external food cues, independent of changes in circulating insulin.

Mild hypoglycaemia (plasma glucose levels of approximately 3.6 mmol/L) preferentially increased activation of the striatum and insula (brain areas that have been previously shown to be activated during fasting) in response to high-calorie food stimuli and induced a greater desire for high-calorie foods. Interestingly, mild hypoglycaemia did not affect the craving for low-calorie foods.

In contrast, normal glucose levels activated the medial prefrontal cortex decreasing interest in food stimuli. Higher blood glucose levels correlated with greater inhibitory control over food motivation. This inhibitory effect was however blunted in obese individuals. The obesity-associated modified responses to circulating glucose levels may account for overeating behaviours in obese individuals.

These data imply that efforts to reduce postprandial blood glucose decreases in healthy individuals can have an effect on neural control of feeding behaviour and desire for high-calorie foods. Therefore, small frequent meals which help maintain circulating glucose levels more stable throughout the day can be a tool in reducing overeating and combating the obesity epidemic.

References: 

1. Page KA, Seo D, Belfort-Deaguiar R, Lacadie C, Dzuira J, Naik S, Amarnath S, Constable RT, Sherwin RS, Sinha R. (2011) Circulating glucose levels modulate neural control of desire for high-calorie foods in humans. J Clin Invest. 121(10):4161-9
doi:10.1172/JCI57873

Story image from Wikimedia Commons.