The diabetes community has lost a giant. Professor Ele Ferrannini passed away on 23 May 2026, leaving behind a community of scientists, diabetologists, endocrinologists, physicians, students, and countless friends astonished and in disbelief. For all of us who have lived and worked in the world of metabolism and diabetes, Ele was much more than a towering scientist. He was one of those rare people whose intellect shaped a field and whose humanity shaped the lives of those around him.

Ele is known to anyone with an interest in metabolism and diabetes for his seminal contributions to the understanding of the pathogenesis of type 2 diabetes and obesity, energy metabolism, and the physiological and clinical implications of therapies such as SGLT2 inhibitors, GLP-1 receptor agonists, and bariatric surgery. His work has profoundly influenced the way we think about insulin resistance, metabolic homeostasis, and diabetes pathophysiology, and it will remain a foundation for future generations approaching the fascinating complexity of intermediary and energy metabolism.

It would be easy to describe Ele by listing his extraordinary achievements: Professor of Internal Medicine at the University of Pisa; Professor of Medicine at the University of Texas Health Science Center at San Antonio; Editor-in-Chief of Diabetologia; President of the Italian Society of Obesity; President of the European Association for the Study of Diabetes (EASD); founder of the European Group for the Study of Insulin Resistance (EGIR); recipient of the Morgagni Medal, the Novartis Prize, the Claude Bernard Lecture of the EASD, the Banting Medal of the American Diabetes Association, and the honour of Commander of the Italian Republic for scientific merits. All of this tells us about the greatness of the scientist. It tells us much less about the man.

Because Ele was not only a scientist. He was a philosopher in the broadest and most human sense of the word: an acute, curious, and endlessly interested observer of life in all its dimensions. He read widely and voraciously, moving with ease from essays to biographies, from social and political thought to history and literature. He loved music and would often skip official dinners to attend a local concert instead. He was a fine art connoisseur, with a particular love for the classics—although I must admit that I never succeeded in convincing him that Rothko was, in fact, a great artist.

He was also a man of habits, and his habits said much about him. He was a dedicated and persevering runner, and every working day, around lunchtime, he would interrupt whatever he was doing, meet a group of friends, put on his running shoes, and run 5 kilometres. He was very fond of his BMW motorcycle, the same one he had saved up to buy as a medical student, and he took great pleasure in riding it through the hills of Tuscany. These details may seem incidental, but they were not. They reflected something essential in Ele: his constancy, his discipline, his loyalty to the things he loved, and his ability to find joy in simple rituals.

And yet, despite an exceptionally full life—scientific, intellectual, and personal, not least as the father of six children—Ele never seemed to be in a hurry. He moved through life at a pace that was distinctly his own, as if he had understood something many of us never quite learn: that life is not to be rushed through, but inhabited fully, attentively, and with pleasure.

One of the most striking things about Ele was his generosity with time. You could knock on his office door and find him deeply absorbed in analysing data or working at his computer, and yet he would stop immediately, invite you to sit down, and begin to talk. And ‘talk’ is perhaps too modest a word. A conversation with Ele could move effortlessly from the data on his screen to a new recording of classical music, from the political moment to family matters, from a scientific hypothesis to a reflection on life. He never made you feel that you were interrupting him or stealing his time. On the contrary, he gave you the sense that he was genuinely pleased to spend that time with you. I am sure many who had the privilege of knowing him will recognise this feeling.

And then there was his humour. Ele had wit, irony, and a kind of lightness that made his intelligence even more enjoyable to be around. Like many truly great men, he had the gift of taking ideas, facts, and problems apart down to the finest detail, but always with perspective and often with a smile. He could laugh at the absurdities of life, and perhaps even more importantly, he could laugh at himself—openly, honestly, and with real amusement. It was part of his charm and part of his wisdom.

But that lightness coexisted with an uncompromising seriousness of character. Ele was a man of deep integrity and a profound sense of ethics. He had no tolerance for shortcuts, superficiality, complacency, or intellectual dishonesty. He could be severe when confronted with them, and his criticism could be sharp. But it always came from principle, never from vanity or malice. He believed that science deserved rigour, that ideas deserved precision, and that people deserved honesty.

Ele was also a generous mentor. Many came to work with him and returned to their own institutions enriched not only by his teaching and scientific training, but by the example of how to think, how to question, and how to remain intellectually free. He was a great scientist, but he was also a generous colleague and a trusted guide for many of us.

I often think of a small episode that, to me, captures him perfectly. At the end of 1999, I was on a ski slope when I received a call on my mobile phone—something Ele himself never owned. It was him. ‘Hi Stefano,’ he said, ‘I was wondering whether you would consider coming down to Pisa.’ I assumed he was inviting me to give a seminar, so I asked him what he wanted me to speak about. He chuckled. ‘You don’t get it. I’m wondering whether you would move to Pisa to take over the Diabetes Unit.’ That was Ele: direct, ironic, understated, and at the same time immensely generous in the trust he placed in others.

We have indeed lost a giant. But those of us who had the privilege of knowing him have lost something even more personal: a presence, a voice, a mind, a way of being in the world. What remains is immense—his science, his teaching, the generations he trained, the ideas he gave us, the standards he set. But what also remains is the memory of a man of extraordinary intelligence, grace, irony, and humanity, who made the world of diabetes richer not only through what he discovered, but through how he lived.