https://diabetes.diabetesjournals.org/content/62/9/3180
Losing weight and then regaining the weight is called weight cycling or yo-yo dieting. This research paper looked at what changes happen to the immune system around fat cells (adipocytes) in people who weight cycle. They found that there are an increased number of T cells (a type of white blood cell) around fat cells in people who weight cycle. An increase of any weight will mean increased inflammation which has negative consequences on metabolism and joint pain.
