Dr. Jules Hirsch

Dr. Jules Hirsch, a physician and renowned clinical researcher who helped change the world’s view of obesity, died on July 23 in Englewood, New Jersey. Dr. Hirsch, 88, was a 1948 graduate of Southwestern Medical College, now UT Southwestern Medical Center.

 Dr. Hirsch had a long career at The Rockefeller University in New York. An advocate of patient-oriented research – in which doctors investigate the mechanism of disease by studying their own patients – he specialized in studies of metabolism, focusing in particular on why some people gain weight and others don’t.

Dr. Scott Grundy, Professor of Internal Medicine at UT Southwestern, who served as Director of the Center for Human Nutrition for 32 years before stepping down in 2013, worked with Dr. Hirsch in the same Rockefeller laboratory for eight years before being recruited to the Medical Center in the early 1980s.

“Dr. Hirsch was a special person in the field of human metabolism and disease, a devoted scientist who made important discoveries in the field of lipid metabolism and human obesity,” Dr. Grundy said. “He did fundamental research on the structure of adipose tissue and developed the framework for much of obesity research that is being carried out today.

“Quite early on, Dr. Hirsch developed the theory that obesity has a strong genetic component. Out of this research came the discovery of leptin, a major hormone made by adipose tissue that controls the appetite.”

In 1995, Dr. Hirsch published a landmark study that explained why weight that has been lost tends to return. The seminal findings, resulting from a decade of studying human subjects in the Rockefeller University Hospital, provided a scientific explanation for what every dieter knows: Keeping pounds off is even harder than initially losing the weight.

The key is metabolism: Reduce a person’s body fat, and metabolism slows so that the body burns fewer calories to carry out the same tasks, and weight returns. That research was crucial to a shift in approach to obesity studies. Previously, fat cells, known as adipose tissue, were considered to be inert storage units for fat that the body burned for energy. As a result, the popular perception was that obese people were to blame for their own condition – that they must be lazy, gluttonous, or lacking in will power.

Dr. Hirsch and others demonstrated through their clinical investigations that, to the contrary, many people are biologically predisposed to be heavy, and that even when they manage to lose weight, biological processes work against successfully keeping it off.

Dr. Hirsch demonstrated that losing weight reduced the size, but not the number, of fat cells people have. He showed that fat cells, far from being inert depots, communicate with the brain, and that the brain keeps track of how much fat is in the body. In 1994, Rockefeller researchers isolated the communicating agent (leptin), which when secreted from fat cells, tells the brain how big those cells are at a given time.

Dr. Jean Wilson, Professor Emeritus of Internal Medicine at UT Southwestern who has long been considered a leading national figure in cholesterol metabolism and endocrinology research, said: “Dr. Hirsch advanced the concept that a calorie is a calorie and that the issue is the relation between caloric intake and energy expenditure. Dr. Hirsch made the discovery that when people gain weight the number of adipocytes (fat containing cells) in the body increases, and when they lose weight each adipocyte loses stored fat. However, the number of adipocytes does not decrease. These cells – empty of fat – are around and waiting for excess caloric intake to allow them to ‘bloom’ again with stored fat. This body of work explained why it is so hard to lose weight permanently.”

Dr. Grundy added, “Dr. Hirsch led a vibrant laboratory that trained many leaders in the obesity field today. He also was a valued adviser for national programs aimed at curtailing the nation’s epidemic of obesity. Dr. Hirsch had an amazing range of knowledge – both inside and outside of medicine – and the opportunity to interact with him was highly rewarding.”

Born in New York City, Dr. Hirsch grew up in Asbury Park, New Jersey, before attending Rutgers University. He left before graduating to study medicine at Southwestern Medical College (now UT Southwestern).

After his 1948 graduation, Dr. Hirsch trained at Duke for his internship and completed his residency at Upstate Medical Center in Syracuse, New York. He spent two years in the U.S. Public Health Service before joining the Rockefeller faculty in 1954.

Dr. Hirsch worked first with Dr. Edward H. Ahrens, pioneering techniques for separating and studying fats in blood and adipose tissue, before establishing his own laboratory. Dr. Hirsch served as Physician-in-Chief of Rockefeller University Hospital from 1992 to 1996. He was President of the Association for Patient-Oriented Research and the American Society for Clinical Nutrition, and contributed as an editor or editorial board member to more than a dozen journals. Among his many honors and awards, Dr. Hirsch was elected to the Institute of Medicine (a division of the National Academies of Sciences, Engineering,and Medicine), and he received the Mickey Stunkard Lifetime Achievement Award from The Obesity Society in 2006.

Dr. Hirsch is survived by two sons, David and Joshua, and several nieces and nephews. His wife, the former Dr. Helen Davidoff, was a noted psychoanalyst who passed away in 2010.

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Dr. Grundy, an elected member of the National Academy of Medicine (1995, then known as the Institute of Medicine), holds the Distinguished Chair in Human Nutrition.

Dr. Wilson, a faculty member since 1960, is an elected member of the American Academy of Arts and Sciences (1982), the National Academy of Sciences (1983), and the National Academy of Medicine (1994, then known as the Institute of Medicine). Dr. Wilson was the first Director of the acclaimed Medical Scientist Training Program at UT Southwestern, and the Jean D. Wilson Center for Biomedical Research was established with support from Dr. Wilson and his sister, Dr. Margaret Sitton, to promote research in endocrinology.