Fig. 2.

Effects of diet-induced obesity (DIO) severity on fat mass (FM) and lean mass (LM) gain. Effect of high-fat (HF; n = 25) and low-fat (LF; n = 23) diet feeding for 10 wk on body weight gain (ΔBW; A), FM gain (ΔFM; B), and LM gain (ΔLM; C). D: histogram of ΔFM/ΔLM for HF and LF rats. Vertical line (1.92 standard deviations plus mean of LF rats) was used to separate HF diet rats in high-DIO and low-DIO. D, inset: effect of diet in ΔFM/ΔLM. For D–G, there were significant differences among groups (high-DIO, n = 10; low-DIO, n = 15; LF, n = 23) measured by a 1-way ANOVA (P ≤ 0.05, see results for details). There was no difference between high- and low-DIO rats in ΔBW, but there was an effect of HF feeding on ΔBW (E) and food intake (in calories; F) after 10 wk of HF or LF feeding. G: ΔFM was significantly different between groups. High-DIO rats showed larger ΔFM than low-DIO rats and LF rats. H: low-DIO rats showed significantly higher LM gain (ΔLM) after 10 wk of HF feeding compared with high-DIO and LF groups. The y-axis indicates means ± SE in all plots, except for C. *P ≤ 0.05 compared with other groups (see Statistical Analysis for details).