Mental exercises and focused mind-intensive tasks appear to induce hunger and increased calorie intake, according to a recent study. Students performing these forms of “intellectual work” were seen to eat significantly more than those simply resting and relaxing their minds.
The study was conducted on 14 college aged students. Each performed a series of three “tasks,” two being forms of intellectual work, the third simply being to rest while seated. Reading and summarizing a certain text was one intellectual task, while a series of mental computer exercises, which included “memory, attention and vigilance tests,” was the second intellectual task. Following 45 minutes of each task, the students were treated to an all-they-could-eat buffet, and their chosen caloric intakes were observed. Blood tests before, during and after each task, were also performed.
From a basic physiological standpoint, the researchers claimed that the mental activity required for the intellectual tasks burns three calories more than resting, which is a relatively small number. It was observed, however, that following text summarizing, the students consumed 23.6% (203 calories) more at the buffet than following resting, and 29.4% (253 calories) more, following the computer mental exercises.
The blood tests revealed that mental activities induced fluctuations in blood glucose and insulin levels. Past diabetic research has connected irregular insulin levels to induced hunger and obesity, which may help explain the findings of this study. Lead researcher Dr. Jean-Philippe Chapuy speculates that, “these fluctuations may be caused by the stress of intellectual work, or also reflect a biological adaptation during glucose combustion.” This means that people eat more after doing something mentally intensive in order to balance their glucose levels.
While a specific solution to this apparent problem was not proposed by the authors, they do believe that the connecting provides at least a partial explanation for the rise in obesity levels, since the technological age has brought about a rise in mentally intensive study and work. “Caloric overcompensation following intellectual work, combined with the fact that we are less physically active when doing intellectual tasks, could contribute to the obesity epidemic currently observed in industrialized countries.” Perhaps an awareness of the established connection found in this study will allow an eating strategy to be implemented that limits this over-eating, such as planning meals before performing mentally intensive tasks.
Source: Defeat Diabetes Foundation: Chaput, Jean-Phillipe. Huppe, Jean-Francois. Pychosomatic Medicine news release. September 2008.