" If insulin fattens those who receive it, as the evidence suggests, then how does it work? The prewar European clinicians who used insulin therapy to treat anorexics accepted the possibility, as Falta suggested, that the hormone can directly increase the accumulation of fat in the fat tissues. Insulin was “an excellent fattening substance,” Erich Grafe wrote in Metabolic Diseases and Their Treatment. "

― Gary Taubes , Good Calories, Bad Calories: Challenging the Conventional Wisdom on Diet, Weight Control, and Disease