Does losing weight intoxicate the body?

It will seem strange, but among the countless benefits that - in case of overweight - weight loss brings with it, there is also a danger to health. In fact, several studies have shown that the loss of body weight, after a low-calory diet or a bariatric surgery, causes an increase in the plasma concentrations of toxic substances.

Many environmental pollutants - for example dioxin, DDT and its degradation products, hexachlorobenzen, polychlorobiphenyls and various other persistent organic pollutants (POPs) - are lipophilic molecules; means that they are related to lipids (fats) and able to dissolve in them.
Once introduced into the human body these substances are metabolized with extreme difficulty (the hepatic metabolism of xenobiotics tends to increase their water solubility so as to allow the elimination of urinary, but unfortunately the liver does not possess effective enzymes for the elimination of POPs). Consequently, the pollutants tend to accumulate, preferentially depositing in the adipose tissue. Therefore, when weight loss occurs, together with fatty acids packed into adipose tissue in the form of triglycerides, the proportion of pollutants stored in the adipocytes is also released.
The discourse can also be seen on the contrary, in the sense that one of the negative effects of obesity is to increase the deposit of persistent organic pollutants in the body. Although the abundance of adipose tissue is protective in the case of acute POPs intoxication, at the same time, preserving substances in the body for a long time, contributes to increasing their chronic toxicity. Not surprisingly, recent studies suggest that these pollutants are related to the metabolic dysfunctions associated with obesity, activating an inflammatory phenotype in adipose tissue. So, more than an excuse to avoid losing weight, the question should be understood as one more reason not to get fat.
Then there is another side of the coin, the one for which it would be the same exposure to persistent organic pollutants to promote obesity. This effect, called obesogenic, would be significant during particular phases of life, which are those of development (from the pre-natal period until the end of puberty); although we hypothesize an epigenetic effect of these pollutants, the relative mechanism of obesogenic action has not yet been clarified.