I fly YYZ-HKG-SIN/KUL often. What I do is to put myself on a "meal clock". Since i usually eat around 7pm at home (in YYZ) and i don't snack, I'll try to time my meals on the stop over and on the plane to match my destination. I find that my sleeping pattern coincides with how long after i finish eating (usually sleep around midnight).

So my flight into SIN usually arrives at about 1am, thus 6 hours before, i'll try to eat my "dinner". That usually means once i get into HKG. So i'll eat a big meal in HKG, then won't eat again (no snacks). When i get into SIN, time for bed!

You can take that a step further (behind) and clock back when you would have lunch (i.e. on the YYZ-HKG flight, 7 hours before landing, or 6 hours in, you eat your "lunch"). Or further back if necessary.

my 2 cents...