Originally Posted by grebletie
Complete horses**t. It's just a way to eat less calories and burn more through exercise.
Agreed.
While the ratio carbs/fat burned by the muscles can be adjusted it depends almost entirely on exercise intensity. You can very slightly increase the fraction fat burned by adaptation to a reduced carbohydrate diet (but performance will suffer) and by
MUSCLE carbohydrate depletion. In the morning your body may have slightly lower
LIVER glycogen stores but the muscle glycogen stores will be nearly fully loaded. The muscles are entirely ignorant to the livers carbohydrate status and will burn its normal macronutrient ratios.