The figure illustrates the simplified model used in the present study. As explained in Methods liver symbolize a surrogate of processes in the tissues with focus on the insulin metabolism. C-peptide denotes the secretion of C-peptide and hence insulin from the pancreatic β-cell. The insulin on the right side of the liver indicates the amount of insulin actually reaching the general circulation influencing the metabolism in peripheral tissues. Most of the insulin execute its action in and is internalized by the liver. Glucose and lipids are both metabolised in the liver, but also in many other tissues, in addition to influencing insulin production and secretion in the pancreas. All these processes can of course be modelled, but at the moment it will impose severe computer challenges. Nevertheless, this highly simplistic model turns out to be very efficient in the latent class analysis (see text).