Not a willpower problem. A cumulative-deficit problem, and it's visible in the numbers long before you feel it in the legs.
By the fourth hour the deficit stops being theoretical. Run twenty grams an hour under target from the start and you are roughly eighty grams down, and the body does not offer a payment plan. That is where most plans quietly fall apart.
By the fourth hour the deficit is no longer theoretical.
The arithmetic
If intake has run twenty grams an hour under target since the start, that is roughly eighty grams owed, and the body does not offer a payment plan.
