A research team has demonstrated that intellectual work induces a substantial increase in appetite and calorie intake. This discovery could help to explain, in part, the current obesity epidemic.
The team measured the spontaneous food intake of 14 students after each of three tasks: relaxing in a sitting position, reading and summarizing a text, and completing a series of memory, attention, and vigilance tests on the computer.
Each session of intellectual work required only three calories more than the rest period. However, despite the low energy cost of mental work, the students spontaneously consumed 203 more calories after summarizing a text and 253 more calories after the computer tests than they did after relaxing.
Blood samples taken before, during, and after each session revealed that intellectual work caused bigger fluctuations in glucose and insulin levels — two critical components in the body’s regulatory and energy machinery — than rest periods.
Jean-Philippe Chaput, the lead author of the study, said that mental work “destabilizes” the levels of insulin and glucose, thus stimulating the appetite, apparently in response to a need to restore the body’s energy balance.
ABC News September 10, 2008
Psychosomatic Medicine September 2008 70:797-804