1 kg. It is enough for two people to eat a catty of prawns. First, it is impossible to eat only one prawn and all other vegetables. Second, prawns are high-protein foods, so you can't eat too much at a time. It is enough for a person to eat half a catty at a time. Precautions for eating prawn: Vitamin C tablets and fruits containing tannic acid, such as grapes, pomegranate, hawthorn and persimmon, should not be taken after eating prawn. If eaten together, it will not only reduce the nutritional value of protein, but also stimulate the stomach and cause discomfort, vomiting, dizziness, nausea, abdominal pain and diarrhea.