Which lifestyle factor is associated with weight gain, according to the text?

The association between shorter sleep duration and weight gain is well-documented in research. When individuals do not get enough sleep, various physiological and hormonal changes occur that can increase appetite and lead to a higher caloric intake. This can stem from an increase in ghrelin (the hunger hormone) and a decrease in leptin (the hormone that signals satiety), both of which contribute to a feeling of hunger even when the body may not need more food. Furthermore, lack of sleep can also lead to increased cravings for high-calorie, sugary foods and decreased motivation to engage in physical activity, both of which can further contribute to weight gain. Thus, shorter sleep duration directly impacts metabolic processes and behaviors that can lead to weight issues.

In contrast, increased physical activity, regular exercise, and healthy dietary choices are generally associated with weight management and loss, as they contribute to creating a calorie deficit and promoting overall health.