"The journey through obesity and chronic metabolic disease begins and ends with the hormone insulin. There is no fat accumulation without insulin.
Insulin shunts sugar to fat. It makes your fat cells grow. The more insulin, the more fat, period.
While there are many causes of obesity, excess insulin (known as hyperinsulinemia) is the 'final common pathway' for the overwhelming majority of them." - Dr. Robert H. Lustig, M.D.