What is known:
• Lifestyle factors during early years affect health outcomes in adulthood, particularly in children with low birth weight.
• Pre-school stage influences children’s body composition and growth.
What is new:
• This is the first systematic review of observational studies examining the association between childcare and childhood overweight and obesity in preschool children.
• ‘Informal’ care is linked to early introduction to solid foods, less physical activity and obesity.