Energy metabolism in feasting and fasting.
Level 5 - mechanism / opinion, no new human data
Narrative review of physiological mechanisms without primary clinical or experimental data.
PubMed 371355 · doi:10.1007/978-1-4757-0734-2_8
What was done
This paper is a narrative physiological review summarizing the metabolic pathways and inter-organ fuel trafficking that occur during balanced nutrient feeding (feasting) and progressive caloric deprivation (fasting and starvation).
What was found
The abstract reports qualitative physiological directions without providing quantitative numbers or statistical metrics. Feasting on a balanced meal increases resting metabolic rate, body temperature, and respiratory quotient while directing excess carbohydrates and dietary lipids into liver and adipose stores, with excess amino acids prioritized for catabolism. During the postabsorptive phase, hepatic glycogenolysis and adipose lipolysis maintain fuel homeostasis. Short-term fasting activates muscle proteolysis to provide amino acids for hepatic gluconeogenesis, but after roughly three days of starvation, metabolism shifts to conserve protein and preferentially utilize free fatty acids and ketone bodies, aided by renal ketone reabsorption.
Why it matters
The paper outlines the coordinated organ-level adaptations between liver, adipose tissue, muscle, and kidney that prevent rapid protein depletion and enable survival during prolonged starvation.
Limits
The abstract contains no empirical trial data, specific sample size, or quantitative measurements. As a narrative review, it describes generalized physiological models without specifying study populations, experimental designs, or the evidence base of the underlying citations.
Cited by
- supports Most humans carry enough stored energy in fat and glycogen in muscles and the liver to survive for at least one month without food.