4-7 months. It is important to start when your baby is excited and interested in food. Breastfed babies are already getting optimal nutrition with a range of flavors and really need very little in the way of solid food before 6 months. Formula fed babies are already getting a one flavor, processed food and may benefit from earlier introduction of solids. Aap recommends exclusive breastfeeding for one year.
6 months. Years ago, breastfeading was frowned on & many made "formula" from boiled cow milk&karo. Since cow milk is designed for calves, infants were fed early & often to make up for deficiences in cow milk. Now that breast is back, or formulas mimic breast, solids are optional. The sitting child is more capable of participating & few sit before 6m. Babies can wait past a year and thrive.
6 months. Six months is the usual age to start babies on solid foods.
4-7 months. There seems to be a window of opportunity between 4 - 7 months or so where introducing solids food is optimal. Starting too early or too late seems to have increased risks for complications down the road. Too early can lead to problems such as allergies or obesity later in life. Starting too late may cause nutritional deficiencies that can delay growth & make it harder to get them to start solids.