This conceptual analysis examines how the body interprets energy availability during sleep and feeding, and why fat-based (ketogenic) metabolism is often mistakenly conflated with starvation or energy deficiency. The paper argues that many biochemical signals commonly interpreted as markers of low energy—such as elevated ketones, AMPK, orexin, and adenosine—carry very different meanings depending on metabolic context. In a glucose-based metabolism, these signals typically reflect insufficient energy supply, but in a well-fed ketogenic state, they can coexist with ample cellular energy and normal satiety.

By disentangling fuel source from energy availability, the paper reframes decades of sleep and metabolism research, showing how ketogenic diets can improve slow-wave sleep, support neurological function, and enhance satiety despite inducing signals traditionally associated with hunger or deprivation. The analysis proposes that sleep and appetite are regulated primarily by sensed cellular energy production—not calorie intake or body fat—and that misinterpreting fat-based metabolism has led to widespread confusion in nutrition, obesity, and sleep science.