Every day, a significant amount of fat is excreted through the skin in the form of sebum. However, this significant calorie loss, which may amount to up to 500 kcal/day in individuals with greasy skin, has often been disregarded in obesity studies. The most important theoretical models of the pathogenesis of obesity, the Energy Balance Model and the Carbohydrate-Insulin Model, need to be re-evaluated taking this into account, and "energy loss through the skin" should be included in the energy-balance equation. This overlooked pathway might partially explain discrepancies in energy balance measurements. Factors affecting sebum production may also affect weight; however, this requires further research.
Keywords: carbohydrate–insulin model; energy balance model; obesity; sebum.
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