Figure 3 of the reference publication has been reproduced using COPASI  4.27 (Build 217)

The paper mentioned that Figure 3 was generated by reducing the intake rate from 12MJ/Kg to 10MJ/kg and it appeared that the initial Fat Mass and Lean Mass was around 50Kg each. But, to generate Figure 3 we had to reduce the intake rate from 12 MJ/Kg to 9.2MJ/Kg with the initial Fat Mass and Lean Mass at 50Kg each.

We also had to change the signs of Psi in Eq(18) and Eq(19) in the paper from + and - to - and + respectively to generate Figure 3(A) and Figure 3(B). We assumed it was a typographical error.