Some new medications in development are also trying to solve for a persistent side effect of existing drugs: Patients who lose fat also tend to lose muscle. This can be particularly dangerous for older adults because it makes them more likely to fall and can worsen osteoporosis.

Novo Nordisk dropped a pile of scientific data on three new experimental weight-loss drugs, including an oral one, showing what appears to be a strategic "something for everyone" plan of attack from the pharmaceutical giant.