It's maltodextrin and designed to be digestible by babies. You can buy it in a fine powder marketed as "Caloreen" from Nestlé. Our pediatrician pushed us to us

It's maltodextrin and designed to be digestible by babies. You can buy it in a fine powder marketed as "Caloreen" from Nestlé. Our pediatrician pushed us to use it in supplement to breast-feeding because the baby was below the expected curve. For what it's worth (not much), our baby that was fed Caloreen has no sugar addiction, quite the contrary. Knowing our pediatrician, I am 99.9% sure that he didn't have any incentive from Nestlé and was just having the baby interest in mind. I am rather blaming the weight curves that are more designed for bottle-fed babies than breast-fed ones, combined with the human tendency to focus on the indicators rather than what they represent.