Changes in predominant fuel supply during fasting
| Duration of fasting (hours) | Predominant fuel | Conditions associated with impaired fasting tolerance of this duration |
|---|---|---|
| 0–2 | Glucose | Hyperinsulinism |
| 2–6 | Glycogen | GSD |
| 6–12 | Gluconeogenesis | GSD 0 Disorders of gluconeogenesis |
| 12–24 | β-Oxidation of fatty acids | FAOD GH/cortisol deficiency |
De Leon et al.12
FAOD, fatty acid oxidation disorder; GH, growth hormone; GSD, glycogen storage disorder.