Designer foods are functional foods targeted toward a particular purpose, such as preventing certain diseases or delivering tailored health benefits. They range from cholesterol-lowering spreads with plant sterols to protein-enriched snacks and probiotic drinks. They sit at the crossroads of food technology, nutrition science and marketing, and every health claim must be substantiated and approved by regulators. Success demands that the functional ingredient survive processing and shelf life at an effective dose, and that the product still tastes good enough for daily use.