Liquid diets based on the AIN-76 formula are described. The diets employ xanthan gum as a stabilizer. Information is provided on how these diets may be modified to meet the requirements of a particular experiment (e.g., variations in water content, type of protein or carbohydrate or fat, etc.). These diets are superior to widely used diets with regard to nutritional adequacy, cost, ease of preparation, versatility, stability, osmolality, and use of natural ingredients. An experiment is described which compares the effects of feeding rats a solid diet or a liquid diet prepared three different ways. The results confirm that a properly prepared liquid diet can produce overweight and obesity.