Once I started sleeping better I experimented with extending my time in bed. When I got to 7 hours total time in bed I slept very well. When I extended to 8 hours total time in bed, I would sleep well for a few days but then find myself falling back into a pattern of insomnia. The key once you have restricted your sleep and are sleeping better is to find your optimum amount of time in bed. Do not listen to those that tell you that an average adult needs 8 hours and 15 minutes of sleep each night.
Many people have a real problem with snacking late at night.
On the other hand, you should not go to bed hungry which is not the problem that most of us have. We have time for one more question. The time seems to vary by individual. Of course, the discipline of the individual is very important. But for some reason I have some people report almost normal sleep in a matter of 4-7 nights.