Protein shakes are typically made from soya, whey, rice, or egg, or blends of these. They come in a variety of flavours, including chocolate, vanilla, strawberry, and others. Many natural varieties use less sugar, colours, and flavours, and often contain added fibre. Some, especially those made for people using shakes as part of a fitness or weight loss programme, may contain additional nutrients. Shakes may come in powdered form, or in cans or bottles, usually in single servings.