Feeding sugar overnight maintains metabolic homeostasis in rats and is preferable to overnight starvation

Lab Anim. 2000 Jul;34(3):301-6. doi: 10.1258/002367700780384735.


Rats are often starved overnight for many different reasons. Overnight starvation causes loss of body and liver weights, depletion of liver glycogen, decrease of blood glucose and loss of amino acids because of gluconeogenesis. Providing pure sucrose cubes as the sole overnight nutrient is a simple, inexpensive way to empty the gastrointestinal (GI) tract, while minimizing liver changes and preventing decrease of blood glucose and loss of amino acids. Adding sugars to the overnight drinking water as the sole nutrient has the same beneficial effects, provided the type of sugar and its concentration allow for sufficient intake and provided hyponatremia is avoided. Feeding sucrose cubes or sugar solutions will empty the gastrointestinal tract as effectively as starvation. In all instances, simple precautions against coprophagy and pica should be taken in order to secure optimal benefit.

MeSH terms

  • Animals
  • Blood Glucose / drug effects
  • Blood Urea Nitrogen
  • Diet
  • Digestive System / drug effects
  • Digestive System / pathology
  • Female
  • Food Deprivation / physiology*
  • Gluconeogenesis / physiology
  • Homeostasis / physiology*
  • Liver / drug effects
  • Liver / pathology
  • Male
  • Organ Size
  • Rats
  • Rats, Inbred Lew
  • Sucrose / administration & dosage*
  • Water Supply


  • Blood Glucose
  • Sucrose