An American research team has demonstrated that intellectual work leads to a substantial increase in calorie intake.
The team measured the spontaneous food intake of 14 students after three tasks: seated relaxation, summarising text, and completing a series of memory, attention and vigilance tests on a computer. After 45 minutes at each activity, participants were allowed to eat as much as they wanted from a buffet. The researchers worked out that each session of intellectual work required only three more calories than the rest period. However the students spontaneously consumed 203 more calories after summarising text and 253 more calories after the computer tests, an increase of 23.6% and 29.4 % respectively, compared with rest. Blood samples taken before, during, and after each activity showed that intellectual work caused much larger fluctuations in blood glucose and insulin levels than resting. The authors suggest that these fluctuations may be caused by the stress of intellectual work. They conclude that caloric overcompensation following intellectual work, combined with the reduction in physical activity which occurs when doing intellectual tasks could contribute to the currently obesity epidemic in industrialised countries. (Glycemic instability and spontaneous energy intake: association with knowledge-based work. Psychosom Med. 2008 Sep;70(7):797-804. Epub 2008 Aug 25).