The association between night eating and body mass depends on age.

Night eating syndrome (NES) is marked by substantial evening or nocturnal food intake, insomnia, morning anorexia, and depressed mood. Originally, NES was described as an eating pattern among obese individuals.However, subsequent studies showed that NES also occurs among non-obese individuals, who appear to be younger than obese individuals with NES. Thus, it has been proposed that NES may lead to future weight gain,which may explain inconsistent findings about associations between NES and body mass. The current study investigated the relationships between age, body mass index (BMI), and night eating severity in a representative sample of German adults (n = 2317). It was found that age moderated the relationship between night eating severity and BMI. Specifically, night eating was positively associated with BMI in participants who were between 31 and 60 years old, but not in younger (<31 years) or older (>60 years) participants. Results indicate that age may indeed play an important role when examining the relationship between night eating and obesity. That is, weight gain may only occur after longer periods of engaging in night eating and, thus, no or only small relationships can be found in younger samples such as students. The positive association between night eating and BMI disappears in older individuals, which may be related to onset of illness associated with wasting.