This paper discusses possibilities to measure healthiness of a food product. It is argued that besides measurement of concentration of biologically active compounds it is also necessary to measure biological activity of such compounds in a food. In doing so, it becomes possible to substantiate health claims associated with a food, as well as to optimize food processing with respect to healthiness. Two examples are given of measuring bioactivity in a food, antioxidant activity of apple juice, and (anti)mutagenicity of heated milk. It is also stressed that optimization with respect to healthiness should be done taking other quality aspects (such as organoleptic properties, safety and nutritional value) into account.