Fig. 5.

Energy intake (A), growth (B), fat deposition (C), and metabolic responses (D and E) of adult Fischer 344 rats to dietary methionine restriction. At 6 mo of age, rats were randomly assigned to receive a control diet containing 0.86% methionine (control group) or a diet with methionine restricted to 0.17% (MR). The diets were provided ad libitum. Food consumption, body weight, and body composition were measured weekly for the subsequent 26 wk. Thereafter, rats were adapted to the calorimetry chambers for 24 h prior to measurement of O₂ consumption and CO₂ production at 45-min intervals for the following 4 days. Body composition was determined by NMR using a Bruker Minispec and used to express energy expenditure per unit of fat-free mass as described in materials and methods. Average EE and RQ were calculated for each animal in each group for the period when lights were on (7 AM–7 PM), when lights were off (7 PM–7 AM), and averaged over both periods to assess total daily EE. Energy intake, body weight, adiposity, EE, and RQ were compared by one-way ANOVA at each time point as described in materials and methods. ^a,bLetters that differ denote P < 0.05.