Energy expenditure of ‘cafeteria’‐fed rats determined from measurements of energy balance and indirect calorimetry.

Abstract

Energy expenditure was determined in rats fed a standard laboratory diet or a varied and palatable cafeteria diet, from metabolizable energy intake and body energy gain over a 15 day experiment. This was compared with measurements of O2 consumption (.ovrhdot.VO2) made over 24 h during the 1st and 2nd wk of the experiment. Metabolizable energy intake was elevated by 50% in cafeteria-fed rats and these animals gained more weight and had a higher body fat content than stock-fed controls. Energy expenditure derived from these measurements was 45% higher in the cafeteria group, and the net efficiency for energy gain was significantly reduced. .ovrhdot.VO2 was increased by 45% in the cafeteria group and the daily energy expenditure, estimated from .ovrhdot.VO2, was identical to that derived from the energy balance for controls and differed by 3% for the cafeteria group. The high levels of diet-induced thermogenesis previously seen in hyperphagic, cafeteria-fed rats were confirmed and the validity of the carcass balance method for estimating energy expenditure was reaffirmed.