Energy storage and reuse in biological systems: Case studies

Abstract

The consequences of energy storage in the body as fat and then reusing it in the metabolism are assessed for seven cases by referring to entropy generation as the criterion for assessment: Case 1: Glycogen and lipids are stored by a person by dieting and then reused. Case 2: Glucose is converted into fat and then reconverted it into glucose spontaneously. Case 3: 2400 kcal of high‐fat diet induced fatty liver disease and then a low‐fat diet is consumed to recover. Case 4: Intermittent fasting by skipping a meal up to 30 days/year. Case 5: Salmon store fat in its body and reuse it later during its journey back to its spawning place. Case 6: Entropic assessment of the female arctic squirrels in hibernation is done. Case 7: Mean exergy cost of active field metabolism of homeothermic/endothermic birds and mammals is compared. Assessments show that energy storage and its reuse generated negligible aging entropy in humans, intermittent caloric restriction via skipping a meal for 30 days in a year may extend the life span approximately 3%. Migrant or hibernating animals store energy and then reuse it with absolutely different purposes than the humans and generate most of their life span entropy.