Current insights suggest a bidirectional relationship between obesity and obstructive sleep apnea (OSA): obesity can lead to OSA, and conversely, the disrupted energy homeostasis observed in OSA may lead to further weight gain. Similar to the mechanism of weight gain observed in sleep deprivation, it is hypothesized that untreated patients with OSA experience dysregulated energy homeostasis with increased energy intake and expenditure, where intake usually surpasses expenditure. However, existing data indicate that treating OSA with continuous positive airway pressure (CPAP) may also promote weight gain. This paradoxical phenomenon may be attributed to a decrease in basal metabolic rate after initiating CPAP therapy, which might predispose patients with OSA to a positive energy balance. However, it appears that dietary habits and disordered eating behaviors have a more significant impact on actual weight changes compared to alterations in energy expenditure. This underscores the importance of integrating lifestyle modifications into the management of OSA.