Older adults sleeping 5 or less hours per night have much greater odds of being obese compared to those sleeping 7-8 hours per night. Men lacking sleep are almost 4 times as likely to be obese, women twice as likely. Reduced sleep also predicts obesity in both children and young adults.
Abdominal obesity increases with sleep loss. Both BMI and body fat percentage are also greater in sleep deprived individuals.
Inadequate sleep is a stressor that increases insulin resistance by elevating adrenal hormones such as cortisol and adrenaline.