Plant-based milk alternatives sold in Spain have a significantly higher median concentration of total carbohydrates (8 g/100 mL) and sugars (5.5 g/100 mL) and a substantially lower protein content than cow milk (4.7 g/100 mL), with the exception of soy-based alternatives, which have a protein content of 3.1 g/100 mL equivalent to that of cow milk.

Manufacturers add sugars and starches to plant-based drinks to improve taste and texture, which raises the total carbs and sugars. At the same time, the natural protein from plants is lower than in cow’s milk, and processing removes or dilutes it, so the final product has less protein — except when soy is used, because soy naturally has as much protein as cow’s milk.