It's a cycle. Eventually you figure out it's beneficial to have a consistent sleep schedule and eat healthier. I still stay up late sometimes and eat poorly too often, but less than I used to. The posted text is a better description of young adults.
Start naturally just going to sleep earlier and naturally waking up earlier.
Whilst it's not a 100% fullproof thing, it tends to help a lot because one just gets sleepy early and feels like going to sleep rather than trying to force it (which, IMHO, doesn't really work) in order to try to sleep enough hours given the time of the day one must wake up at in order to work.
I do this once in a while and just try to keep it going, though eventually some longer period of heavy stress gets me back to 3 cups of expresso a day and not sleeping enough hours to wake up rested most nights :/