Early 20th‑century diabetes treatment focused on severe caloric restriction to reduce glucosuria, often leaving patients markedly underweight. The discovery of insulin in 1921 shifted therapy toward glucose control, but weight management remained secondary. Only in recent decades have clinicians recognized that both underweight and overweight pose risks in diabetes, prompting integrated approaches that address nutrition, medication, and exercise together. This evolution highlights how therapeutic goals expand as our understanding of metabolism deepens.