Eli Lilly (LLY 2.13%) sells a broad range of medicines, from cancer and immunology drugs to treatments for migraine. The pharma giant's presence across several treatment areas has helped it grow earnings over time. But, in recent years, one particular product portfolio has stood out and driven double-digit revenue growth: drugs to help people lose weight.Right now, Lilly sells tirzepatide, commercialized as Mounjaro for type 2 diabetes and as Zepbound for weight loss, though doctors have prescribed either o ...