It is important to start this diet very slowly just like when you wean a baby onto solid foods. Start with small quantities and introduce foods one by one with your current formula. Each child will respond differently so it is impossible to give you a step by step timeframe, you really have to see how they tolerate certain foods. I started slowly and introduced more and more foods. The most practical way is to slowly replace formula with blended food, so if your child has 100cals of blended food than reduce the same amount of formula in calorific value. The aim is to eventually replace all of the formula with high calorie, low volume, nutritionally balanced meals. It can be a struggle to achieve high calorie/low volume and this is where you really need to get to know your foods and the calories they contain.