Dr. Theodore Van Itallie, an obesity expert and leading metabolic disease investigator, died in Old Lyme, Connecticut on September 14. He was 99. The author of over 200 publications, Dr. Van Itallie was the first to demonstrate that weight loss was a function of calorie reduction, not changes in the protein or other composition of the diet. He publicly refuted the “calories don’t count” weight loss class and often supplied a commentary on the recent fad diet to the popular media with accountable medicine. Dr. Van Itallie was born in Hackensack, New Jersey in 1919. He graduated from Deerfield Academy, Harvard College and Columbia University’s College of Physicians and Surgeons. He was a Navy Medical Corps captain (j.g.) and was involved in the Pacific Theatre. Dr. Van Itallie, who returned from Japan in 1948, finished his residency training at St. Luke’s Hospital in New York and accepted a position of studies and teaching at Harvard Medical School. In 1957, he returned to St. Luke’s as Medicine Director. St. Luke becomes a teaching hospital under his management at Columbia University. Dr. Van Itallie stepped down as Medicine Director in 1975 to run the first center for obesity studies funded by the NIH. Van Itallie retired from the Obesity Research Center in 1988 and continued his dedication to medical research, publishing over 48 journal papers, advising on clinical research and paying particular attention to ketone esters as a therapeutic agent for Parkinson’s and Alzheimer’s disease. He was a dedicated amateur historian who wrote numerous articles on the history of the west coast of Florida and served as president of the 2001-2003 Florida Historical Society. The first marriage to Barbara Cox by Dr. Van Itallie ended in divorce. Sallie Newton Calhoun, his second wife, died in 2012. His five kids survive him: Lucy Borge, of Quogue, NY, Princeton’s Theodore Jr., NJ, Bethesda’s Christina Van Itallie, MD, New York City’s Elizabeth Van Itallie and Katharine Van Itallie, six grandchildren and four great-grandchildren.