Christina Szalinski/Kaiser Health News

Formulas for toddlers are a burgeoning business in the United States: Sales of the drinks more than doubled in recent years as companies convinced parents that their little ones needed the liquid boost. But many experts warn that these products, designed for children ages 1 to 3, fill no nutritional needs beyond what is available in a typical toddler diet, are subject to less regulation than infant formula, and are expensive.In addition, some parents feed the toddler versions to infants even though they do not meet federal standards for infant formula and may not provide babies with adequate nutrients to sustain their growth.