studies show that static stretching actually makes you weaker if performed before weight training. try to do ballistic stretching before lifting, and static stretching after lifting.
i would eat the sweet potatoe with your PRE workout meal. also, get more carbs with your POST workout meal. maybe have your protein shake with some apple juice?
you cant just switch your diet that drastically and expect your body to handle it. you need to slowly add in these extra meals, and your body will slowly get used to it.
