Obesity rates remain at historic highs, despite a persistent focus on eating less and moving more, as guided by the energy balance model (EBM). Explaining obesity as a disorder of energy balance rests on principles of physics without considering biological mechanisms that could promote weight gain. An alternative theory, the carbohydrate insulin model (CIM), states that increased fat deposition in the body- caused by the hormonal responses to high carbohydrate diet-leads to a positive energy balance.

American Medical Association decided to define obesity as a disease. Not all medical experts agree with American Medical Association. However, there is general agreement that obesity is a complex state with multiple functional changes that require a wide range of interventions for prevention and treatment. There are many factors involved, including genetics, lifestyle, psychological and developmental.