Weaning is when you introduce solid food into your baby's diet alongside their usual breast/formula or combination milk feeds. Weaning is advised to start at 6 months of age as up to this point babies get everything they need to grow and be healthy from their milk.
Introducing solid food too early can increase the chance of your baby becoming an overweight baby or child. Being overweight greatly increases the chance of health problems such as diabetes in childhood and later in life. It is also important to wait until your baby can eat food safely to reduce risks such as choking.