Intentional weight loss can increase health risk in the long‐term, despite short‐term benefits, because human adipose tissue is widely contaminated with various lipophilic environmental contaminants, especially persistent organic pollutants (POPs). Recently, chronic exposure to low POPs has emerged as a new risk factor for common metabolic diseases and cardiovascular diseases. The amount of POPs released from adipocytes to the circulation increases during weight loss, thereby increasing POPs exposure of other critical organs. Possible harmful effects due to release of POPs during (...) weight loss are opposite to those usually expected from losing weight. It is speculated that this tradeoff can explain recent puzzling findings on intensive weight loss. The presence of POPs in adipose tissue adds a challenge to weight management and an optimal strategy of weight management needs to consider both fat mass and dynamics of POPs. (shrink)