How sugar can cause depression requires further investigation; however, several mechanisms, such as imbalanced levels of insulin and blood glucose (insulin resistance), effects on thyroid hormones, deviation/dysregulation in the mesolimbic dopamine system related to short-term boosts in mood through longer-term adverse effects, increased levels of inflammatory and oxidative stress biomarkers, alterations in the gut–brain axis, and increased production of toxic molecules such as advanced glycation end-products (AGEs) have been proposed [65]. This evidence concerns the gene INS and depressive symptom measurement.