This man is a 55 year old type 1 diabetic. For 31 years he was supposed to be rotating daily positions for his insulin injections. However, he had been mistakenly injecting into the two same spots resulting in two large fat balls on his stomach. This case was reported in the New England Journal of Medicine and is known as insulin-induced lipohypertrophy.
Insulin is a hormone which controls how much fat we store in our fat cells. Therefore, we want to avoid chronically high levels of it, which can lead to excessive weight gain and other health problems. The best way to do this is by reducing sugars and starchy carbohydrates in our diets.