Minnoch's weight continued to increase steadily until his hospitalization in March 1978 at age 36 due to cardiac and respiratory failure. That same year, he broke a record for the greatest difference in weight between a married couple when he married his 110-lb (50 kg) wife Jeannette and later fathered two children. Minnoch was diagnosed with massive generalized edema, a condition in which the body accumulates excess extracellular fluid. Upon his hospital admission, it was estimated by endocrinologist Dr. Robert Schwartz that over 900 lbs (408 kg) of his overall body mass was retained fluid.
He was discharged from the hospital after 16 months on a strict diet of 1,200 kcal (5,000 kJ) per day. He weighed 476 lb (216 kg; 34.0 st), having lost approximately 924 lb (419 kg; 66.0 st), the largest human weight loss ever documented. However, he was readmitted to the hospital just over a year later in October 1981, after his weight increased to 952 lb (432 kg; 68.0 st). With his underlying condition of edema being incurable and difficult to treat, the decision was made to discontinue treatment, and he died 23 months later on September 10, 1983, aged 41. At the time of his death, he weighed 798 lb (362 kg; 57.0 st) with a Body Mass Index of 105.3.