We propose a method to create a wide range of human body shapes from a single input 3D anatomy template. Our approach is inspired by biological processes responsible for human body growth. In particular, we simulate growth of skeletal muscles and subcutaneous fat using physics-based models which combine growth and elasticity. Together with a tool to edit proportions of the bones, our method allows us to achieve a desired shape of the human body by directly controlling hypertrophy (or atrophy) of every muscle and enlargement of fat tissues. We achieve near-interactive run times by utilizing a special quasi-statics solver (Projective Dynamics) and by crafting a volumetric discretization which results in accurate deformations without an excessive number of degrees of freedom. Our system is intuitive to use and the resulting human body models are ready for simulation using existing physics-based animation methods, because we deform not only the surface, but also the entire volumetric model.