Bad kidney usually refers to renal insufficiency. Patients with renal insufficiency are not recommended to eat foods high in salt, fat, potassium and phosphorus. 1. High salt: such as salted vegetables, various kinds of pickled foods, and salty snacks. Eating too much high-salt food may increase the burden on the patient’s kidneys, aggravate edema, cause high blood pressure, and in severe cases, may even lead to acute left heart failure. 2. High fat: such as fried, animal fat food, etc. Eating too much high-fat food, aggravate gastrointestinal burden, and may aggravate hyperlipidemia. 3. High potassium: such as Chrysanthemum coronarium, black dates, pea shoots, etc. Because kidney disease can lead to potassium metabolism disorders, hyperkalemia is easy to cause the risk of cardiac arrest, so patients with renal insufficiency should strictly limit potassium intake. 4. High phosphorus: such as mushrooms, nuts, dairy, etc. High phosphorus can easily lead to renal osteodystrophy. If patients find kidney disease, it is recommended to go to regular hospitals in time and standardize the treatment under the guidance of doctors.