Energy balance

Pharmacological activation of AMPK in skeletal muscle promotes glucose transport and fatty acid oxidation while suppressing glycogen synthase activity and protein synthesis.

Activating AMPK (through exercise or certain drugs) shifts your muscle metabolism to burn fuel (glucose and fat) and store less glycogen, while simultaneously pausing muscle building (protein synthesis). This is why timing nutrition around workouts is critical: you need to manage the trade-off between burning fuel and building muscle.