Food and water restriction protocols: physiological and behavioral considerations.

Food and water restriction protocols are common in animal research, yet they often elicit discussion and controversy among institutional animal care and use committee members who review them. Determining a single standard by which all restriction protocols can be evaluated or performed may not be realistic. However, information about the physiologic and behavioral impact of food and water restriction can provide a basis for making rational judgments about these issues in general. This review will discuss the physiologic and behavioral consequences of food or water deprivation periods of 24 h or less and of chronic restriction schedules, with special reference to protocols that use food or water restriction as a motivational tool for behavioral training.