Glycogen

Glycogen is the stored form of glucose, primarily held in the liver, and its adequate storage is a central marker of metabolic health in Ray Peat's framework. 2 Peat argued that a healthy liver, supported by proper thyroid function, should store enough glycogen to sustain the body for at least eight hours, allowing a person to sleep through the night without activating stress hormones. 3 He noted that hypothyroidism and elevated estrogen severely impair the liver's capacity to store glycogen, leading to a rapid depletion of this reserve. 2 This impairment creates a natural craving for sugar, as the body struggles to maintain blood glucose, a symptom Peat personally experienced until he began taking thyroid hormone. 1

The physiological consequence of depleted glycogen is a cascade of stress responses. When liver glycogen runs out, the body first releases adrenaline to mobilize any remaining glucose, causing symptoms like shakiness and coldness. 3 If this fails, the body shifts to a more destructive mode, secreting cortisol, which breaks down the body's own tissues—starting with the thymus gland and progressing to muscles and skin—to convert protein into sugar. 2 Peat emphasized that this catabolic state is the essence of harmful stress, whereas a person with full glycogen stores can easily go 12 to 18 hours without food and without triggering this tissue-wasting process. 2 The brain is the primary consumer of glucose at rest, making a steady supply from glycogen critical for cognitive function and preventing the neurological symptoms of hypoglycemia. 5

The liver's capacity for glycogen is substantial but finite. Dinkov and Roddy have cited research indicating that the liver can store approximately 500 grams (about one pound) of glycogen, and that de novo lipogenesis—the conversion of carbohydrate to fat—does not become a significant pathway until these stores are chronically saturated through massive overfeeding. 2 Fructose is particularly effective at refilling hepatic glycogen, with one infusion study showing it produced about 360% more glycogen than a glucose infusion. 4 This rapid storage is cytoprotective, as fructose has been shown to continue supplying ATP to cells even when oxidative metabolism is poisoned. 4 The frequent nighttime waking that plagues many people is interpreted as a direct sign of poor liver function, indicating that glycogen stores have been exhausted during the night, forcing a stress response that disrupts sleep. 7

Several factors are known to degrade the liver's ability to store and manage glycogen. Endotoxin from intestinal bacteria places a great burden on the liver, and a fatty liver, whether from alcoholism or non-alcoholic sources, physically impedes glycogen storage. 2 A deficiency in nutrients like choline and vitamin A can promote the accumulation of fat in the liver, further compromising its function. 8 To restore optimal glycogen storage, Peat and Dinkov have recommended substances that support liver health and reduce fat accumulation, including niacinamide (in doses under 500mg), aspirin, vitamin E, vitamin K, gelatin, glycine, and taurine. 7 Coffee and thyroid correction are also cited as key interventions that help a person go longer without food stress by supporting the underlying metabolic rate that governs glycogen synthesis. 6