Whey protein is a type of dietary supplement made from whey, which is a by-product of cheese production. It is a complete protein, meaning it contains all nine essential amino acids that your body needs. It is popular among athletes and bodybuilders for its muscle-building benefits.

Meal replacement shakes are drinks that are designed to replace a meal. They typically contain protein, carbohydrates, fats, vitamins and minerals, and are meant to provide a healthy, balanced meal. They usually contain fewer calories than a full meal, which makes them a good option for those looking to lose weight.