A liquid diet is a diet that is mostly made up of liquids, or soft foods that melt at room temperature (such as ice cream). A liquid diet usually helps provide lots of hydration and helps maintain electrolyte balance. It is often prescribed for people who suffer with gastrointestinal illness or damage, or before or after certain types of medical tests or surgeries that involves the mouth or the digestive tract.^[1]

A liquid diet is not recommended outside of hospital or medical supervision. Negative side effects include fatigue, nausea, dizziness, hair loss and dry skin. These effects are said to disappear when the person starts eating.^[2]

A clear liquid diet is made up of a diet only contains transparent liquid foods that do not contain any solid particles. It is sometimes called a surgical liquid diet because of its perioperative uses. This includes vegetable broth, bouillon (excepting any particulate dregs), clear fruit juices such as filtered apple juice, clear fruit ices or popsicles, clear gelatin desserts, and certain carbonated drinks such as ginger-ale and seltzer water. It excludes all drinks containing milk, but may accept tea or coffee. Typically, this diet contains about 500 calories per day, which is too little food energy for long-term use.^[3]

A full or strained liquid diet is made up of both transparent and opaque liquid foods with a smooth consistency. People who follow this diet may also take liquid vitamin supplements. Some individuals who are told to follow a full-liquid diet are also allowed to eat soft foods such as strained meats, sour cream, cottage cheese, ricotta, yogurt, mashed vegetables or fruits, etc.^[1]