The book argues that most weight loss struggles are not due to lack of willpower or overeating, but rather a slow or dysfunctional metabolism . Suárez introduces the idea of a "broken metabolism" — often caused by yo-yo dieting, insulin resistance, stress, or hormonal imbalances — which prevents the body from burning fat efficiently, even when eating fewer calories.

The book outlines a multi-step approach to restoring metabolic function:

Frank Suarez no inventó un concepto nuevo, sino que décadas de investigación endocrinológica en un lenguaje coloquial. Sus bases científicas incluyen: