The clear liquid diet: when is it appropriate?

Closer attention to the clear liquid diet and its therapeutic applications has been prompted by critical reviews of nutritional enhancement in the clinical environment. The aim of ongoing research has been to uncover the optimal nutrient complement in various patient groups as well as the most beneficial mode of nutrient delivery. Route of feeding is often the essential determinant in effectiveness of nutritional support. Many studies have sought to demonstrate the superiority of enteral versus parenteral nutrition, whereas comparative studies with clear liquid diets are sparse. Recently, identification of key nutrients in the support of malnourished or immunocompromised patients has been emphasized. Although total parenteral nutrition has undisputed applications in specific patient groups, it has lost favor for general application because of its negative impact on immunocompetence. Efforts have thus been redoubled to explore the potential of the gastrointestinal tract, with the derived benefit in immunosupport for many medical and surgical disease states. Until recently, the clear liquid diet had not received close scrutiny and had retained an unchallenged position in certain applications (eg, bowel preparation). This paper summarizes the published, theorized, and potential benefits as well as the limitations of the clear liquid diet.