im just saying what works for me. i DO NOT advocate doing 2 a days everyday, thus that only spells burnout. If you do 2-3 days of 2 a days, that will work.
i suggest starting out doing simple crap like if you drink a pop a day, cut that out. drink water. you can still eat whatever greasy hamburger/fries, but down the line, try to eliminate that stuff too.
people who try to go cold turkey on their diet, and also go blast workouts with tons of volume/intensity often end up back where they were in the first place.