They found that "Compared with sleep, total sleep deprivation was associated with an increased activation in the right anterior cingulate cortex in response to food images, independent of calorie content and prescan hunger ratings."
According to an article about this study by Kathleen Blanchard, RN:
"Christian Benedict and Helgi Schiöth, of the Department of Neuroscience at the University also showed that lack of sleep leads to increased hunger.
"According to Benedict, findings from their newest investigation revealed, “After a night of total sleep loss, these males showed a high level of activation in an area of the brain that is involved in a desire to eat.”
"The study participants were shown images of food during the brain scans, with and without a good night’s sleep.
"Benedict adds, 'Bearing in mind that insufficient sleep is a growing problem in modern society, our results may explain why poor sleep habits can affect people’s risk to gain weight in the long run. It may therefore be important to sleep about eight hours every night to maintain a stable and healthy body weight.' ”
Over the twentieth century, average sleep duration for U.S. citizens declined from about 9 hours daily to about 7 hours daily. During that same time, per capita energy intake and obesity rates both increased.
McAllister et al suggest "that a myopic emphasis on" changes in food habits and activity levels as causes of weight gain has "caused the popular media, and perhaps some researchers as well, to neglect the potential contributions of other factors to the balance between energy intake and expenditure."
"Our questioning of the big two stems from two points. First, the evidence supporting various elements of the big two as contributors to individual or population levels of obesity is often quite weak. Second, even though some elements of the big two do very likely play some role in influencing obesity levels, we believe that an unquestioned assumption of their preeminence has led to the possibly ill-advised expenditure of public effort and funds on programs aimed at reducing population levels of obesity and has also reduced the exploration of other potential causes and the alternative obesity reduction programs that might stem from their identification."
McAllister et al point to evidence showing that sleep deprivation and nine other factors––including microorganisms, epigenetics, increasing maternal age, greater fecundity among people with higher adiposity, assortative mating, environmental endocrine disrupters, pharmaceutical medical interventions, reduction in variability of ambient temperatures, and intrauterine and intergenerational effects–– have have all played a role in promoting the obesity epidemic.