In nature, food is typically not available on a continual basis, and laboratory animal health is substantially improved by less than ad libitum access to chow (McCay, Crowell, & Maynard, 1935; Weindruch & Walford, 1988). That said, restricted access to food has the potential to cause distress to laboratory animals, so its use must be clearly justified and refined to produce the least chance of impairing the welfare of the subject. Therefore, the Animal Research Committee (ARC) has established the following guidelines.

  • The least restriction that will achieve the scientific objective should be used, and refined procedures should be instituted to limit it. For example, restricted access to food is often used in behavioral training studies, but it can be minimized when a highly preferred food reward item is used as positive reinforcement.
  • Because of variation in food requirements and nutritive status among individuals of the same species, average guidelines for food intake are not appropriate. Food intake data should therefore be based on age-, sex-, and strain-matched controls.
  • Animals on a restricted diet must be monitored daily for continued good health. Weight must be monitored at least every other day and records on body weight must be kept, unless indicated otherwise in an approved protocol. Other parameters (e.g., body condition scoring) for measuring health appropriate to the species should be monitored in consultation with Division of Laboratory Animal Medicine (DLAM) veterinary staff. Rats, for example, tend not to drink when food is unavailable and should be observed for signs of dehydration.
  • Restriction or deprivation or use of schedules of restricted access that will produce more than 20% decline in body weight is discouraged and must be scientifically justified in an approved protocol.
  • Investigators utilizing food restriction/deprivation protocols must communicate with the animal care staff. To prevent animals from receiving improper rations, the staff must be informed about periods of restriction/deprivation and about rest periods when full or supplemental food can be provided. To communicate to the veterinary and animal care staff during periods of food restriction/deprivation, special treatment cards must be placed on the cage indicating that the investigator’s laboratory will be responsible for feeding animals, and the duration (start and end dates) for this special feeding schedule must be noted on the card. Special treatment cards may be obtained from DLAM; please consult with them as to the proper card(s) to use and the information they must contain.


    1. McCay, C.M., Crowell, M.F., Maynard, L.A. (1935). The effect of retarded growth upon the length of life and upon ultimate size. J Nutr 10, 63-79.
    2. Weindruch, R. & Walford, R.L. The Retardation of Aging and Disease by Dietary Restriction (Thomas, Springfield, IL, 1988).
    3. Guide for the Care and Use of Laboratory Animals. National Research Council, 2010.
    4. Guidelines for the Care and Use of Mammals in Neuroscience and Behavioral Research. National Research Council, pp. 49-61, 2003.
    5. Interdisciplinary Principles and Guidelines for the Use of Animals in Research, Teaching and Education. The New York Academy of Sciences, pp. 7-8, 1988.

    Approved 11/13/00; Revised 1/28/02, 7/26/04, 10/23/06, 7/26/10; Updated 1/18/11, 7/26/19