Why are you advised not to wean a baby before they are 17 weeks old?

Well, honey, you don't want to mess with a baby's development by weaning them too early. Before 17 weeks, their little bodies are still getting used to the idea of solid foods, so cutting them off too soon could lead to nutritional deficiencies. Let the kiddos enjoy their milk for a bit longer before you start pushing them towards the broccoli.