For example, these days it's commonplace to work In many families, both parents work, which makes it harder to find time for families to shop, prepare, and eat healthy foods together. Sourced from: http://www.health.harvard.edu/staying-healthy/why-people-become-overweight

9.Health Conditions Some hormone problems may cause overweight and obesity, such as underactive thyroid (hypothyroidism), Cushing's syndrome, and polycystic ovarian syndrome (PCOS).

Lack of sleep increases the risk of obesity in other age groups as well. Sourced from: http://www.nhlbi.nih.gov/health/health-topics/topics/obe/causes